Unable to use won area from Bandits

Hello,
I'm at level 19. I've won some area from bandits but I'm unable build anything on it? I'm not getting why this is happening? con anybody suggest me what to do for this.
TIA
julaie

build a storage first

mean to say at free area...?

you have to put a storehouse as the first building in any new area you win

then u can build