The Izhevsk Shooting Club has produced a high quality seven part video series on the disassembly and reassembly of the AN-94 rifle. Unfortunately it is all in Russian, but most TFB readers will be able to follow what is being explained the first four parts of the series. Part five and onwards could really use a translation.
Part 1: How the fire controls, stock, sights are used and adjusted.
Part 2: Field stripping the AN-94, how the gas system and flash hider work.
Part 3: How the bolt, carrier, piston and balanced recoil works.
Part 4: Further disassembly of the rifle. How the trigger mechanism functions.
Part 5: Disassembly of trigger mechanism. Cleaning.
Part 6: How the safety and selector function (?).
Part 7: Reassembly.
[ Many thanks to jdun1911 for emailing me the link. ]