Punctuation practise commans

This is a punctuation practise writing it helps me with a lot of things especially writing it is great and helpful. but this is the one where my literacy teacher helped me with.

Explanation writing

How to Prevent yourself from getting sick.

Why do we have school

S we have school so we can get good 

grades in school and be smart

E so we can be smart when we grow up

E And to have real goods friends at school

C so as well you can have a good job when you grow up.