Keep in mind that experienced goalkeepers generally prefer to perform their own release rather than to have that changed to an indirect free kick so choose your options carefully and step in only when the potential interference is blatant and/or when the players are inexperienced and/or when you have warned the opponent but the opponent interferes anyway (the caution is for unsporting behavior but ignoring an actual warning from you adds an icing of dissent).
USSF answer (June 2, 2008): No player is allowed to interfere with the goalkeeper’s ability to put the ball back into general play. The referee should stop play and restart with an indirect free kick for the goalkeeper’s team from the place where the infringement occurred. (Please remember the special circumstances for restarts after infringements occurring within the goal area.)
The goalkeeper may pick up the ball whenever they want in the penalty box after an opponent last touched it, but they need to be wary when the ball comes back to them from one of their own teammates... If a teammate uses their head or chest to send the ball back, then the keeper is allowed to handle the ball.
Goalkeeper interference is when an opposing player stands deliberately in front of the goalkeeper to block them from playing the ball. If the goalkeeper has hand control (possession) of the ball, an opponent cannot interfere with or challenge the ball.
Interference can also include active physical or verbal distraction of the goalkeeper by an opponent as well as blocking the view of the goalkeeper. A player who is in an offside position when the ball is played toward him by a teammate and who attracts the attention of an opponent, drawing that opponent into pursuit, is guilty of interfering with an opponent.
While the ball is in the possession of the goalkeeper, it may not be challenged for or played by an opponent in any manner. An opponent who attempts to challenge for a ball in the possession of the goalkeeper may be considered to have committed a direct free kick foul.
each team must be designated as a goalkeeper. The goalkeeper must wear a different color shirt from his teammates so that everyone can easily distinguish the goalie. The goalie can only use his hands inside the penalty area. LAW 4 - Player’s Equipment Players must wear the same colored jersey or shirts. All youth programs require shin
When the goalkeeper has control of the ball, an opposing player may not touch it or try to kick it. If any part of the goalie is touching the ball, this is generally considered control. Penalties can be severe including a goal kick and red card for players that endanger the goalkeeper.