how to join siege of winterfall and arena of glory?:)

There's no explanation on how to do this :) There's no such option on the cross-server website. What's the point of participating in Winterfall Training Camp when I can't play Siege? :) No alliance in my kingdom has 25 active members. No alliance I've fought with had 25 members... In Glorious Battle, a seed alliance can have T5 users, but in Winterfall Siege, a new player like me can't enjoy the game :)