From what I can tell you'll need to go into the main game properties and add controls for Player 2 - move up, move down etc. and make sure they're for Player 2.
Next you'll need to create another XBox Controller object and go into its properties - select Controller 2 and match up all the controls below to the actions you just set up in program properties.
Finally if you go to the platform behaviour for the object you wish to be used by Player 2 and select Player 2 in the properties. That should sort it :) Also remember if you've got anything read by events to pick Controller 2 or change (1) to (2) if there's no controller selection.