I have understood the Preview:
You have the 2d Map and on the map 30 clans maximum. Clanleader can say which province is the next under attack. So every Team Member attack this Province and every clan member from the other clan defended it. Every battle is 1 on 1. So the Army is always one vs one, but you can support your clan member but then you only control
one unit from the Army, your clan member the rest of the Army. Maybe so you can playing 20 vs 20 battles
2 vs 2 (" Armys vs 2 Armys) or other options doesnt go in the MP clan
Campaign, there goes in normal MP Battles.