A minimum of two players line up parallel with each other one metre apart between the five-metre and 15-metre lines. Usually, the hooker of the team in possession throws the ball in while his opposite number [may] stand in between the touchline and the five-metre line.
All players not involved in the lineout, except the receiver (usually the scrum-half) must retire 10 metres.
The ball must be thrown in straight down the middle of the lineout and the hooker must not cross into the field of play while throwing in. If the throw is not straight then the throw is given to the opposition or a scrum awarded.
Jumpers can be lifted by their teammates below the waist, but the opposition’s jumpers must not be obstructed, barged or pulled down.