i am unsure what to do with the "primer, pistol" and other guns along that name same with case ammo? not sure how to use it...

The basic idea is that you use them to create ammo at an ammo press bench.

You'll need the Primer(s), some Lead, Powder (Different for each weapon's ammo type) and such... All of which you can breakdown other bits of ammo you don't use to acquire, at the bench too (Check the options towards the bottom of the list).