GASP! You have a terrible infection indeede... planning the second BEFORE the 1st is even done?!?! [:D]
Well, I missed the rest of the question...the tips.
To put in the pivot pin.... go get a 1/4" clevis pin (w/ lots of holes in it). Put the pin in on the opposit side that the pivot goes. Line up one of the holes...drop in the spring throught the pin and into the lower. Put the detent and use a small nail or something that fits in the hole to push the detent into lower. While holding detend down, turn the pin so the clevis pin holds in detent/spring in. Now, with the AR pin, push the clevis pin out. IF done right, the spring/detent should engage the AR pin slot. Oh, do this step in a clear plastic back, incase the spring and detent goes flying, it will be "in the bag" (pun intended).
Get yourself a roll pin punch set. This will help in putting in the trigger guard pin and the pin to hold the bolt hold open. To keep from maring the lower when installing the bolt hold open pin, put some masking tape (a few layers) on the lower so incase you do slip, you won't scratch the lower. The punch set can also be used to help put the trigger and hammer in (line all up and put the punch in the holes, smaller dia.) And then use another punch (or a plastic mallet) to put the pin in.
You'll have to start the roll pin for the bolt hold open first...since holding in the catch and trying to start the pin is well... difficult. But I guess I'm stating the obvisoue.
Make sure all pin holes are clean. Using a drill bit to make sure they are free of "obstructions" helps. Take your time, don't rush things.
Dang it, I can't think of anything else....