How do i get cloaks on march of empires?

New gamer. Been told about "citadels" in March of empires... Don't know what it is... Can someone explain?

what is citadel in March of empires

I like to work with a team and know what I'm doing but for three days all I got was smart ass replays from my so call teammates I try to comply with what ever the promote told me. all I get is nothing I'm going back to television.