At this age you want to keep it fun! I have a game we play in summer camps with this age and it is called "walk the dog".
I pair up the kids
I tell the kids the ball is the dog and he needs to go potty and they need to pass the ball (dog) back and forth while moving across the court to the other side (outside). If they drop the ball (dog) they must wipe the floor because their dog just messed on the carpet and then they start over. I have them all compete at the same time. When you first start this game they will not be able to do it but after a few time they will. Most kids enjoy playing if you make it fun and learn ball control at the same time. Have fun!

Check this website out for some ideas on how to teach very young players to start playing volleyball.

http://www.volleybalnederland.nl/English.htm