When do I show a yellow or red card, and how do I handle a dangerous tackle?

Cards (handbook section 46): umpires and League Administrators can issue yellow and red cards to any player, official or spectator.

• Yellow, player: leaves immediately via the interchange, cannot return for 15 minutes of playing time, and may be replaced straight away.
• Red, player: leaves immediately, cannot sit on the bench or return for the rest of the match (including breaks); a replacement may enter after 15 minutes of playing time.
• Team official or spectator: must leave the vicinity of the playing surface (no Coaches Box, change rooms or spectating) for 15 minutes (yellow) or the rest of the match (red).
• Two yellows in a match: no further part and an automatic one-match suspension.
• Failing to leave immediately on a yellow makes it a red offence.

Dangerous tackles (section 54): you may pay a free kick, yellow or red card for rough conduct. Cues are a vulnerable head or body, excessive rotation or slinging, one or both arms pinned, lifting the legs, or a tackle that drives or has two actions. Guide:

Instant red cards may apply to inherently dangerous tackles, such as slinging where the ball player cannot brace, lifting a player without returning them to the ground with reasonable care, or pinning the arms so they cannot brace. A yellow can be upgraded by the Field Umpire, Umpire Coach or League Administrator.