I am a gunsmith?

I am not a gunsmith.  I did, however, assemble my first gun this week (or at least the lower half of one).  The recipe is easy: one AR-15 stripped lower, one AR-15 lower parts kit, one AR-15 carbine stock kit.
The stripped lower is a block of aluminum with a bunch of holes and slots in it.
The lower parts kit contains about 40 parts, installed into the lower to allow it to shoot.
The carbine stock kit is 6 pieces and installs onto the stripped lower.  It's the butt-stock and recoil system.

The process is about 10 steps, each step using about 4 parts.  Following the guidance of a pair of youtube videos, including one by CMMG, the maker of my lower parts kit.  The CMMG video was really helpful, as it referenced the parts by the color bag they were shipped in.  I was nervous about the pin installation, as you normally use a hammer and a pin punch.  However, in the second video the installer uses a pair of Kniplex pliers, which have parallel jaws, to squeeze the pin into the hole.  I don't have one of these, but I do have a locking adjustable wrench (Chapman Tiger-Lock) which also keep the jaws parallel.  Using it, I was able to install all the pins without needing the hammer or punches.  The rest was just making sure I lined holes up and put the pin through them.  It was simple.

I have a second stripped lower, but I think I'll go for a higher-end build, with a quality trigger, grip and stock.