Clans allow players to unite under one coat of arms and form a strategic alliance that benefits all its members. Being in a Clan allows players to develop rapidly, stay protected from enemy attacks, and take part in specific tournaments that are only available to Clan members.
At the beginning of the game, you will be prompted to create a Clan or to find one in your Kingdom.
To create a clan, click the purple button. You will be prompted to choose a name for your new Clan, a three-letter Clan tag, and an emblem. You can also select whether your Clan should be private, request-only, or open for all to join. Select your Clan's primary language and click "Create a Clan." It will cost you 7.5K Gold to create a Clan. 
To join an existing player-created Clan, click the green button, which will take you to your Kingdom's Clan rankings, where you can browse through the existing Clans and join one or submit an application to do so.