As you can see from my post count I'm also a total newbie. Never owned an AR before. Shopped around, bought a stripped RRA lower at a local gun show. Picked up the rest from the Equipment Exchange here, put together an all-RRA gun with a 16" flat-top upper for $600. I'm really impressed with the quality.
I put the lower together like the previous poster, using the tagged post describing how to do it. I had to flip back and forth between the sections a few times to clear up questions, but it took me maybe 45 minutes to do. A lot of the time was trying to figure out what was wrong with the safety selector detent, simply because it was very, very, stiff the first few times it was moved, but then it started working just fine.
It's really very easy, just follow the directions, take your time. In the worst case scenario if it goes together wrong it won't work and you can take it apart and do it again, but that's not likely to be necessary if you use care the first time.