What are the passing rules, and what happens if the ball is dropped?

• A player in possession may not kick, pass, flick, knock, throw, hand off or otherwise propel the ball forward to another player, intentionally or not. The penalty goes to the defending team at the mark where the ball was propelled forward, unless advantage is applied.
• A player may not intentionally propel the ball forward over an opposition player and regain possession (penalty to the defending team).
• A pass is a lateral or backward delivery between attacking players and can include a flick, knock or throw.
• If the ball is dropped or passed and goes to ground during play, there is a change of possession at the spot where the ball first hit the ground.
• If a player mishandles the ball and it is accidentally knocked forward into any other player, there is a change of possession.
• An attacker cannot pass the ball into a defender seeking a rebound or a restart of the touch count (penalty to the defending team).
• A player must not pass or deliver the ball after a touch has been made (penalty to the defending team at the point of the infringement).

Source: FIT Playing Rules 5th Edition, definitions and rules 9.4, 9.6, 10.6, 11 and 12.7.