Typically if you request a game and it is added to the site, you will be made the moderator. Current moderators can add more moderators as they see fit for the game's popularity. If all current moderators are inactive, there's a thread in the Site section of the forum where you can request to be added as moderator. Typically, site staff expects you to be a runner of the game and to have contact info connected with your account in order for this to happen.