To create a ball, you need to right-click on a live pufferfish while holding 8 skins in your hand
Throw the ball - LMB
Throw the ball harder - LMB when running or jumping.
Throw Power Slider - SHIFT
Pick up the ball - SHIFT next to the ball
/ballskin - change the skin of the ball
/ballsreload - reload the plugin. Requires volleyball.reload permission