You cannot add modules to a game you didn't create (For that matter, you cannot add Modules to an existing game, you must create a game based on them. You can add Addons to an existing game if you created it.). If you want to switch your purchase to a gift, you can email <a href="mailto:team@roll20.net" rel="nofollow">team@roll20.net</a> with the details and see if they can work it out for you. (They are quite busy with the influx of users to the platform, so cut them some slack on the timing of a response!)