When you are in the game you can 'get to the mod' in different ways. When you launch the game you will see a new window at loading screen identifying the mods in your game, click ok and load. Unzip the files and place the packages into the Packages folder you created with instructions at MTS.
To begin, I recommend, Master Controller, Master Controller Cheats, and Overwatch Then travel over to Nraas Industries and download the mods appropriate for you patch. All you have to do is make sure your game has the mods folder (instructions at MTS)