Here is the url for soccer world's site.
There are directions on the bottom of their home page.
It is reffed mostly on the honor system. If you feel you got hit call yourself out. They have reffs who will call you out only if they see you clearly got hit but they are there mostly to make sure everyone plays safe.
The nice thing about reballs is that you can shoot as much as you want. I'm not sure if they will let us bring pods though.