I volunteered to help with my oldest kids soccer one year, and had a blast for the next 10+ years. Most areas, age 4 you get to have a little practice time, so figure out what you want them to learn (like 1 or 2 things at a time) and keep it simple - how to touch the ball, how to change direction, etc. But start getting coaching licenses, attend local and state coaching clinics, go become a referee - so you can become the coach your kids will need as they get older. It is very rewarding teaching kids the skills they need to become good at something, that they can do more than they think they can, that they can only learn to succeed at something by not being afraid to try it in a game - I loved seeing the light go on in their eyes as they "got it" - won't happen at 4, but stay the course and you'll see what I mean.