Firing Pin HELP

Hey I'm a new user and I need some help/advice/knowledge.

A few years back my father tried to restore his old model 94, 30-30, post 64 with a new stock, and let's just say he isn't mechanically inclined. It ended up not going back together correctly and in the end lost a few pins and a firing pin.
I finally found it and am currently trying to restore it, I've narrowed down the missing parts to the:

Finger lever pin, finger lever pin screw, sight plug screws, and a firing pin.

Alright so here is my problem, I am not knowledgeable enough to know if the firing pin itself is the only component needed or if I also need something else in order to hold the firing pin in place. The last time my father attempted to fire the weapon before he gave up and stored it, he said the firing pin fell out the back of the bolt. I would like to avoid the same problem, so any help or advice at all would be a HUGE help, thanks y'all.