I am assuming you already have a Lionel Fastrack layout?
Unless you are running MTH's command control system (DCS) there should be nothing you will need.
MTH even makes transition pieces to enable you to use their track with your Fastrack.
Did your MTH set come with a remote control? I know they make a basic remote control system for some RTR (ready to run) sets. If it did check the owners manual for "Conventional control" I am almost positive it will run on a conventional Lionel transformer. I don't have any MTH locomotives or DCS, but I know where to find the information if we need it.
If you tell me what you already have (track, transformer and Command Control system if you do have Command Control, TMCC or Legacy) and what MTH set you got for Christmas (congratulations!) I should be able to help you more.