Yes, you'll need:
1. A lower parts kit or LPK (trigger, hammer, pistol grip, springs and pins that all go into the lower-and is an easy installation via YouTube)
2. Buffer, buffer spring, buffer extension tube, end plate and your choice of stock
(both #1 & 2 above would also be included in a lower build kit or LBK)
3. Your choice of barreled upper assembly would probably be the easiest.
4. Your choice of bolt control group or BCG which is the bolt and bolt carrier. (sometimes the BCG is also included in the upper)
You could also build your upper from a stripped upper, but that would require a few more tools. If you went with a barreled upper assembly, you could get away with putting the whole thing together with a few punches, hammer, Allen wrenches, and YouTube. It's a pretty easy job and would take just a hour or so.
I think I got everything.....
