Android: Saving a Single Checkbox in Navigation Drawer Fragment

I am brand new to android programming and know this question has popped alot, although, I can seem to decipher the code to understand how it works. What I need is to save the checkbox state when switching to another fragment. But also I don't just need the code, I need to understand how exactly to program more if needed. I am really sorry that you might get upset as this seems easy, but I need a step by step explanation how to do it.. Please can someone assist me.

Kind Regards