I could use some help...

[nisils14]

Essential parts to any AR platform rifle.

1. lower receiver
2. lower parts kit
3. rec. extension/ buttstock kit
4. upper receiver
5. bolt carrier group
6. charging handle
7. barrel
8. gas block/FSB
9. gas tube and associated pins
10. handguard
11. magazines

And depending on your parts selection you might need the following

1. delta pack kit
2. ejection port cover kit
3. forward assist kit
4. muzzle device
5. barrel nut
6. Rear sight parts

There is details I'm missing but that's most of it. It's a metric shit ton of options for just about every part imaginable, you just need to research it and figure out everything you want.
Watch these:
http://www.youtube.com/user/MidwayUS...ch?query=ar+15