When you're coaching a group of kindergarten-age youngsters, the focus should be first on fun -- followed closely by the fundamentals of the game and safety. At this age, kids don't tend to have a lot of experience with throwing, catching and batting, so your practice sessions should focus on helping your players gain basic skills and confidence.
Very Basic Drills
Softball skills break down into four basic categories: hitting, throwing, catching and fielding. Plan your practices so that you cover all four categories. Start with basic catching and throwing drills, giving each pair of players plenty of room so they don't endanger others with wild throws. Start with soft, pliable balls instead of "real" softballs, to reduce the risk of injury. Then break the players into hitters and fielders, and give each hitter the chance to hit the ball off a T and run around the bases. Teach the fielders what to do when the ball comes to them, which at this level, typically involves catching or retrieving the ball and then throwing it to first base. Scrimmages are also a great way to teach common scenarios.