Etiquette and regulations regarding playing positions.
(taken from World Bowls Regulations).

Position of players
In relation to the rink of play –
Players at the mat-end of the rink who are not delivering a bowl must stand at least 1 metre behind the mat. 
Players at the head-end of the rink and who are not controlling play must stand behind the jack if they are members of the team which is in possession of the rink.and behind the jack and away from the head if they are members of the team which is not in possession of the rink.
Players should stand on the surrounds of the green if the jack is in the ditch; or well clear of the head if it is not possible to stand on the surrounds
N.B.  players at the head end of the rink MUST stand and keep hands still during preparation and delivery from the mat end, and stand away from the rink number and/or rink markers.
N.B. if passing another rink on the bank, you must wait until a bowl has been delivered, if bowling is being effected towards you.
N.B Do not allow your body to cast a shadow across the jack.
N.B. Do not stray onto other rinks when walking up and down the green. Move quickly to the other end of the rink, behind the head to allow your skip to bowl as soon as they are ready.
Roles of players in various positions
In all team games it is the Skip’s job to direct the play. Other players should play the shot directed by the Skip. The skip and their number 2 in triples or 3 in rinks, will often discuss the next move before the skip moves to the mat.
In a game with teams of four, known as Rinks, the ‘third’ should advise the Skip when required to do so.
In Triples or Pairs the Second or Lead may do this. Other players should not interfere unless invited to do so. 
The Skip
The Skip takes sole charge of the team, and his / her instructions shall be observed by his / her players. 
The Skip usually keeps the score card. 
The Skip will give clear instructions to their team as to the required shots.  They can indicate the line required, or the bowl that you should be attempting to reach.  Once the bowl is delivered, they should retire to 2 metres behind the head to pass the head to the opposing skip.
The Skip keeps a record of all shots scored for and against his / her team and at all times retains possession of the score card whilst play is in progress. He / she shall enter the names of all the players on the score card; shall compare their record of the game with that of the opposing Skip as each end is declared.
The Third (in a rink) or The second (in a triple)
To be able to play well in this position requires you be capable of following very specific bowls delivery instructions given by your skip;  generally bowling accurately and tactically on both line and length with either the forehand or backhand, as is necessary to help to build a good head .
This position also puts you in charge of the head when your Skip is at the other end.
You must inform the Skip of the situation as it develops; and, when necessary, advise the Skip as to the shot to be played. You will need chalk, a measure, and wedges.
You must agree the score with your opposite number, be responsible for marking your side’s touchers, and above all keeping your Skip informed. 

Advising the Skip

This is most important when the bowls have been disturbed after the Skip has left the head. It can be assumed the Skip has studied the head before leaving it and does NOT need to be told anything (unless you are asked) before the skip bowls the first bowl. (Sometimes things look quite different to the skip from the other end)
Tell the Skip whether the score has changed after each of the skip’s bowls, and any relevant information which should influence the choice of his next shot. You cannot convey everything so confine yourself to what the skip needs to know. It can be helpful if you do this by hand signals as well as by verbal information.
 N. B. The Skip may or may not follow your advice.
Sometimes the skip may not feel confident in making the shot you suggest. 
However, if you think the skip is contemplating a risky shot, be emphatic.
Agreeing the Score
This is done with your opposite number ONLY, and other team members should NOT offer their opinions – unless there has been an obvious mistake such as a bowl being wrongly identified.  
Do not allow anyone to kick away or move any of the bowls closest to the jack until you are both satisfied with the score.  It is also good practice to place winning bowls on a towel to avoid any possible confusion with other nearby bowls.
Beware of your opposite number (or anyone else!) indicating the score to his Skip before agreeing it with you – he may be hoping you will not ask for a measure!
If in doubt, always measure rather than waste time looking from every angle.
The one who thinks they are holding shot will ask for the number of shots they think they hold, and it is usual for the other to measure if they don’t agree. If either of you has a disability it is good practice to offer to do all the measuring.
Clearly indicate the agreed score to your skip (who keeps the score card) by pointing the number of fingers up or down as shots won or lost, or by slapping your arm that number of times, as well as calling out – e.g. ”1 up” or “2 down”.
Playing as a No 2 – in a Rink
This requires you be capable of following specific bowls delivery instructions given by your skip. Therefore, you should be capable of bowling well on both line and length with either the forehand or backhand when requested.
Hence, you should be able to improve on or consolidate the bowling efforts of your No.1. so as to help to build a better head for the subsequent bowlers in your team.
The number 2 in a rink changes the scoreboard once the score has been agreed.
The Lead
Your most important role in the game is to get one or more of your bowls as close to the jack as possible, and preferably behind it rather than in front of it.  Any very short bowls that may get in the way later on are undesirable.
Playing in this position is often badly underrated, because if you can consistently manage to get one or more of your bowls close to the jack on every end, without delivering too many very short or very wide bowls , you will have a skill that is to be much admired and most welcome by your team!
That said, the No.1 position will usually be given to any new bowler starting on match play until they gain more experience of the game, and of match etiquette in particular. (See separate sheet on this!)
As the No.1 bowler you are also responsible for placing the mat with the front edge at a minimum of 2 metres from the ditch (or further up the green if directed to do so by your skip) with the mat straight and with the middle of it running along the imaginary centre line between the numbers at each end of the rink.
Please expect to have your mat placement corrected sometimes, as directed by your skip.
Careful initial placement of the mat is important, because many bowlers use the mat to choose their bowling line.
(N.B.  A crooked or misaligned mat may be straightened or realigned by any bowler during the match, but it cannot be moved forwards or backwards after initial placement.)
It is usual for the visiting friendly team to have “visitors jack” i.e. be the first to have their No.1 place the mat, bowl the jack and bowl first.
It is also usual in more competitive matches to have 2 trial ends, when you will have the privilege of choosing the length of the jack when you bowl it, whereas on all the other ends the skip will usually stand at the length that he wants you to bowl the jack to.
It is usual for each bowler to deliver one bowl on the forehand and one on the backhand during a trial end.
The skip may also ask you to bring the mat up, to change the run of the green and maybe confuse the opposition.
Consequently, being able to bowl the jack close to the centre line and to the length asked for by your skip is a crucial skill.   If you deliver a jack that is too short (N.B. it must be a minimum of 23m from the mat) or into the ditch your opposite number is allowed to re-position the mat and must bowl the jack correctly instead, although you will still bowl first.
 (N.B. Useful tip! All bowlers should be watching carefully all their team’s bowls and all the opposition’s bowls, to help them assess the green’s behaviour, just as much as they should be watching their own!)
When playing as a No.1 in a Rink, you will invariably be allowed to choose whether you bowl on the forehand or the backhand with both of your bowls.
When playing as a No.1 in a triple your skip may choose to advise you on which hand to bowl your third wood.
As a No.1 you pick up the jack and the mat and get ready to place the mat and bowl the jack ASAP, when you win an end; or collect all the bowls with a trolley, when you lose an end. Take care not to collect up any bowls close to the jack before the no. of shots has been agreed!
All Players.
It is worth emphasising that the head must not be disturbed by any player until the shots have been finally agreed. When the Thirds or Skips are deciding the shots the other players should stand well back from the head and give them the space to do so. 
During the game encourage your team mates, do not criticise them. Commend good shots and learn to accept that flukes are a part of the game. Sometimes they go for you, sometimes against.
Skips should also note that even when a poor bowl is delivered by one of his team members that some encouragement is needed. If you can’t think of something positive to say, say nothing. Also, be aware of body language, a skip turning their back after a bowl is delivered or shaking their head can be seen by the player, which can demoralise the bowler.