What I know is that you can play clan wars if you are in a clan of at least three clan members. You can join a clan or create a new clan and invite members to your clan. If you want to join a clan, you can search and apply a clan through the COD application using mobile device. If you want to create a new clan, be sure to have at least three clan members 24 hours before the clan war starts. I have also tried to check its updates for next clan war through this link - Beachhead Studio (beachheadstudio) on Twitter . If you are in a clan already, you can wait for the clan war to start and select the the specific mode in Multiplayer to be played. In addition about Clan Wars, you can also check this link - Activision Support . I hope this would help you.