How do I signal touch and show which team throws in?

The law (Law 6.26)

• When the ball or ball-carrier goes into touch or touch-in-goal, hold your flag up.
• Stand at the place of the throw (the mark of touch) and point to the team entitled to throw in.
• Lower the flag when the ball is thrown in, unless the thrower stepped into the field, the wrong team threw, or a quick throw was not allowed.

World Rugby's signal: raise the flag with one arm, move to the mark of touch and stand there, pointing with the other arm towards the team entitled to throw.

Practical steps from World Rugby guidance

1. Raise the flag as soon as the ball is in touch.
2. Mark where the ball crossed the line by putting your foot on the touchline.
3. Once a quick throw can no longer be taken, raise your arm on the side of the team to throw in.

The ball is in touch when a loose ball touches the touchline or anything beyond, or a held ball or the ball-carrier touches the touchline or the ground beyond (Law 18.1). A player who jumps from the field, catches the ball and lands back in the field has not gone into touch (Law 18.2).