Expansion using marble keys??

How do you expand your island using the marble keys? I have a ton of raw marble that I can craft into the marble keys and then it says I can use those to expand my island but I don't know how to. I don't see any option. Do I need a certain amount before the option becomes available? I'm level 101

Storm8: EricAxKayLana - Island: Land of Kai

(Edited by EricAxKayLana)

Expansion

Curlyee·11/7/2019

You will need to clear the land nearby the bridge (left side) to unlock the land on the other side. But while you are clearing the land you can get a jump start on crafting keys, it takes a lot!?

(Edited by Curlyee)

EricAxKayLana·11/8/2019

Ouuu okay thank you for the tip!

(Edited by EricAxKayLana)

What do you think?