What you need:
* Tennis ball
* Blank wall
* Trusting parents
You will get on your knees a few feet back from the blank wall, and just work on using soft hands to field grounders. Be sure to get your hand out in front to receive the ball, and work on bouncing it at various heights, to simulate bad hops and soft grounders.
If you break something, just blame it on the dog.
Here is a kid that works through a nice progression, if you’re looking for inspiration!