You can search by a Clan name or ID Tag, or browse through the Clans list. You can also use the filter system to search Clan requirements, such as total trophies, location and member count.
When you have found a Clan, tap the join button. Applications to open Clans will be accepted immediately, whereas Clans with closed applications will be sent to the Clan Leader for review.
Once you join a Clan, all open applications to other Clans will be deleted within 48 hours. You can change Clans as many times as you like but can only be eligible for one weekly Clan Chest reward. Your personal progress will move with you when you move between Clans.