Hello,

Pretty FAQ ---> here.

To choose who participates in a Clan War, go to the same old "swords" War button. You will see the "Start War!" icon. Tap on it.



On the next screen you will see the list of all your clan members and their personal War Preferences. Clan in the example is ineligible since it doesn't have enough members, but anyways.

If you're satisfied with the members' personal preference, no action is required. If you want to change it from in to out, or vice-versa, tap on the respective button to invert the selection for that player.



After Leaders are happy with the line-up, click on Start War and the matchmaking will start.


Hope this helps. But really, read the FAQ.