What do English summer camps in China usually involve?

I am working with my school to try and make a summer camp for grade 3 up to grade 8 this summer.
What should I plan when I do this?
Should I make the materals myself or should I just follow a book?
How many classes a day are typical for a summer camp?
What kind fo format should I follow?

What do training center (we are a public school not training/theifing center) usualy do?

Any help would be great