I'm new to all of this as well and my AEG is currently getting downgraded and I've been doing a lot of research and reading as to maintenance and what not. This link from Airsoft GI was a ton of help when it comes to the anatomy of an AEG. I'm one of those anal types when it comes to maintenance so when I go pick up my gun I'm going to ask as many questions as I can and if they have time run me through the breakdown of the gun so I know what to do, what not to do and what to leave for the gun docs. Notes will be taken because $500 is a lot of money and last thing I want to do is spend more money on improper maintenance.
Airsoft 101