Play it! If you are new to mech games, play the Vanilla until you feel you got the hang of it, then run to the NexusMods and download at least the YAML mods, which will apply the other zilion mechnics and customizations the Battletech universe has. Youtube has a lot of good mods list for you to try as well. Now get to the OZ and scrap the OpFor Lance, Merc!
For beginners in the Mechs world that love tactics this is a great game, after finishing the campaign you should go search for the RogueTech set of mods that will overall the game.
