A basketball court is 50 feet wide and 94 feet long. The sidelines serve as boundaries as well as the baselines. On the outside of these boundary lines are fans, player benches, coach's seats, and even the media and scoring table.
There are 2 ways for the sideline to create a turnover. The first is if the ball goes out of bounds. Whoever touched the ball last will forfeit possession and the other team will get the ball. The second way a turnover happens is if a player with the ball steps out of bounds. This includes any part of the ball handler's shoes or any other part of the body. You must know where you are on the court at all times, and if you are close to the sideline or baseline, you must be careful not to accidentally step on the boundary line.
Throw ins are the way that the game resumes play after a stoppage. This could be after a timeout, foul, commercial break, and at the beginning of halves and quarters. To complete a throw in, a player must keep both feet planted outside the boundary line, and pass to one of his or her teammates. If the player doesn't pass the ball within 5 seconds of the referee blowing the whistle, the ball is turned over to the other team. This is to prevent someone from waiting an eternity to pass the ball into play. One way that teams practice throwing the ball into play are set plays.
Set plays are plays that are set up before a game during practice or warmup. They usually happen on throw ins, so that there is a perfect moment for the set play to start. Most set plays include a verbal cue that signals that the set play has begun. All players have a roll, this could be running to a certain area on the court or setting a screen. Set plays can be pivotal as being able to get the ball inbounds on a throw in can sometimes prove difficult. Set plays can also be run to get a perfect last shot in the game if there is very little time left on the clock.