I paid for and of course downloaded "The Ballad of *** Tony". How do I get it to play instead of Niko? Really confused and kinda pissed. Thank you for the help.

put in your copy of the originally GTA IV and load that. then it should ask you if you want to play TBOGT, if it doesn't then when Niko's game loads push pause and go to new game and you should be able to choose TBOGT.