Filling out FAFSA help...!

I was F-1 student, now our family got a green card so I’m about to register for FAFSA and other grants.
I know this is stupid, but I really need help as I want to make sure everything is correct.

On FAFSA, there’s only one page that you actually put numbers down (Tax informations)
and my mom sent me 2015 tax return files. Do we use 2015 tax return to fill out 2017-2017 fafsa?

Which form are we using?
Theres like FORM 8879, FORM 1040 (Individual income Tax Retunr)
How should I do it?
I have no idea…

never mind i got it!