In order to use the mods provided with this follow these steps:

  1 - Open the "Frosty Mod Manager 1.0.7.0" folder, then run the "FrostyModManager.exe" file
  2 - If required, on first launch, run a game scan (Refresh) if you don't see the NEED FOR SPEED UNBOUND icon; otherwise click on the relative icon and continue
  3 - Once the Mod Manager window appears, drag the aforementioned "NFS_Unbound_Back_to_Rockport.fbmod" file to the left column (list of available mods), then double-click on the "NFS_Unbound_Back_to_Rockport" mod which will appear in the right-hand menu with a white check
  4 - Now you can start the game with the mod inserted by pressing "Launch" at the top of the Mod Manager window

NOTE
To be on the safe side, I always recommend backing up your save before playing any mod.
To do this, go to the Documents folder of your PC, then go to the "Need For Speed(TM) Unbound" folder (at least for the Origin version) and make a safety copy (backup) in a safe location.

Have fun,
Max_91_Ita