Weplay is probablly not the best resource for your inquiry-there simply is not enough space for directions and needed graphics. Try checking your school library, bookstore, or on-line volleyball resources. Best advice for this limited space:
Keep it simple and make it fun. No one should be standing around. Use drills that require high repetition with a lot of continuous ball contact. Go to your local high school and watch a practice or two and simply the drills that you see there.