How does the self-pass work, and when can the ball go into the circle?

FIH Rule 13.2: the player taking a free hit may play the ball themselves, which is a self-pass.

Attacking free hit inside the 23-metre area (13.2 f):

• The ball must not be played into the circle until it has travelled at least 5 metres (not necessarily in one direction) or been touched by a defender.
• A player taking a self-pass may play the ball as many times as they like, but it must travel 5 m before they play it into the circle.
• Once a defender has touched it, anyone, including the taker, may play it into the circle.
• The ball may be played high over the circle to land outside it, unless that's dangerous or the ball is legitimately playable by another player inside or above the circle during its flight.

Free hit within 5 m of the circle:

• Taken immediately: defenders inside the circle and within 5 m may shadow a self-passing player around the inside of the circle. They may not play or try to play the ball, or influence play, until it has travelled 5 m or been touched by a defender who can legitimately play it.
• Not taken immediately: all other players must be at least 5 m away before it's taken.

Defenders still wearing penalty corner kit may pass straight away from a defensive free hit, but may not self-pass (13.3 n).

Any other playing of, attempt to play, or interference with the ball by a player who wasn't 5 m away should be penalised.