How does tagging work, and what happens after a set of tags?

• A team in possession has a maximum of six tags. A player in possession is tagged when at least one of their tags is removed by an opposing player, or when a tag is accidentally removed by the player or accidentally falls off.
• A team in possession is allowed five successive play-the-balls. A handover occurs after the 5th play-the-ball if the team is tagged a sixth time (at the point of the 6th tag), if the team commits an accidental breach that changes possession, or if a player is tagged in the opponent's in-goal (the changeover is 10 metres out from the goal line). The play-the-ball after the 6th tag is not counted for the tag count.
• The referee indicates the 5th tag by raising one arm vertically with fingers and thumb outstretched.
• Accidental breach: where an accidental breach such as a knock-on or forward pass changes possession, the following tag is a "zero tag".
• Losing possession: if a tagged player accidentally loses possession, a handover occurs.

Source: NRL League Tag Laws of the Game (Official 2018), International League Tag Laws section 7.