I think you have to create a game and choose your purchased module. Volo's example: <a href="https://wiki.roll20.net/Volo%27s_Guide_to_Monsters#How_to_Access_the_Volo.27s_Module" rel="nofollow">https://wiki.roll20.net/Volo%27s_Guide_to_Monsters#How_to_Access_the_Volo.27s_Module</a>