Instructions
Insert your "Grand Theft Auto 4" game disc into your PS3's disc drive. Turn your PS3 on.
Select the "Users" option in your PS3 main menu.
Select the "Create New User" option in the users menu.
Use your PS3 controller to enter a name for the user into the field that appears, then choose the "OK" option to save the new profile.
Select the new profile in the "Users" menu, then select the "Grand Theft Auto 4" option in the profile menu to create a new GTA 4 account.