Need Help with Beginner Program

I have finished other elements of the program, but I am not sure where to go on this one. Yes I am a beginner. I don't know how to perform these divisions with leftovers and such and how to make it all work. Any help would be appreciated.

Determine and report the number of large, medium, and small pizzas you need to order

For every 7 guests, order one large pizza

For every 3 guests left over, order one medium pizza

For every 1 guest left over, order one small pizza

And i know the modulus operator "%", but I just can't seem to put everything together ha