You will hear a lot about must have tools - but the armorer's kit is really equipped to disassemble the unit's machine guns. Putting together an AR doesn't take much, and tools needed to service 400 in constant use aren't necessary for the first one.
This sticky explains a lot:
http://www.ar15.com/forums/t_3_4/22...__GAS_BLOCK___Step_by_step_instructions_.html
The lower roll pin for the trigger guard has to be done without putting any extra pressure on the ears. I taped up a pair of vice grips, placed the guard inside the ears, and then pressed the pin in. The guard then supports the ears.
The front pivot pin is not troublesome at all if you turn it at least 90 degrees and use it to depress the detent. It then pushes in, rotate it to click the detent in the slot, done.
Beating roll pins into holes is a advanced skill I wouldn't recommend for any new builder, much less buying an expensive set of specialty punches that can only be used for that job. Same for an upper block - you only tighten up the one receiver, a wood block or vice jaw inserts will hold an upper. Tightening the barrel nut really just means turning it to the notch so the gas tube can pass, the 30-30-30 retightening does help seat the threads. By then you can see the next notch is likely already partially exposed, just bear down until it lines up. The 80 pound max torque is 20 under the worst case lower limit the barrel pin will shear or damage the nose. If it's that bad, squaring the upper slightly would be some help. Most don't need it.
I used a 18" pair of channel lock pliers to tighten my barrel nut. I wasn't concerned about little nicks in a hidden part, I didn't want to spend upwards of $100 on tools for a one time build. That was money needed for a better barrel.
It's NOT to your advantage as a first time builder to mess with pinning an FSB, buy the barrel already done as they are sold for less than separately.
Once done, don't buy cheap ammo, shoot it with military spec to check function - then try the import fodder if you want. It's not loaded to do the job correctly as many have found out - the AR in milspec form is tuned to milspec ammo, not low powered plinker trash. Get quality magazines, and it won't cease to amaze with it's light weight and accuracy.