If you're just starting with leglocks I would focus on learning a few entries to the main positions like Ashi Garami/Single Leg X and Inside Senkaku, then learn how to control a person and keep them in those positions as long as possible. Depending on how your training partners and school feel about heel hooks, maybe just finish with straight ankle locks. You can find a decent amount of information for free online if you hunt hard enough.
Stephan Kesting just released a new instructional which is pretty awesome, goes through entering positions, controlling, finishing, etc etc. It is $97 though (At the moment at least, price is gunna go up to $177 at some point soon) so if money's an object then maybe get Reilly's.