Rounders is an outdoor game often referred to as a deviation of baseball. While the structure of the game is somewhat the same (both use a ball and bat) the rules and general play are different.
Get the equipment. Rounders uses its own regulation gear, including the ball, bat and bases. These bases can be simple poles staked into the ground or poles attached to flat bottom plates.
Learn the rules. Understand the unique relationship between the pitcher and the batter. In rounders, the pitcher is referred to as a feeder and the batter as a striker. The striker has the right to approve or disapprove of the feeder and the way that the ball is thrown.
Learn the nature of the sanctuaries and castle. These are the names of the bases. Essentially, the goal is the same: to get past every sanctuary and into the castle.
Read change of play rules. The striker must get in contact with the ball. The system of outs that determines team change is also different.
Study some of the informal conventions. In addition to formal rules, there are some other commonly understood principles of play that can impact a practice game.
Play practice games. Assemble teams and play through a few rounds of the game, careful to discuss any unclear aspects of the game rules as presented or previously studied.