When do I blow the whistle, and when is the ball dead?

Question

Accepted Answer

Under Law 6.8 you blow the whistle:

To start and end each half.
To stop play (you can do so at any time).
To indicate a score or a touch down.
To caution or send off an offender, and a second time when the penalty or penalty try is awarded.
When the ball becomes dead, other than after a failed conversion kick.
When the ball becomes unplayable.
When a penalty, free-kick or scrum is awarded.
When it would be dangerous to let play continue, or when you suspect a player is seriously injured.

You deem the ball dead (Law 6.9) when it is in touch or touch in-goal (but not when a quick throw is permissible), is grounded in in-goal, a conversion has been attempted, a try, penalty or dropped goal has been scored, the ball or ball-carrier touches the dead-ball line or anything beyond it, or the ball hits anything above the playing area.

If the ball or ball-carrier touches you and neither team gains an advantage, play continues. If either team gains an advantage in the field of play, a scrum is awarded to the team that last played the ball.