My Lands: Black Gem Hunting

i have seen the icon for warehouses but can't construct any. is there a science to study which allows me to construct one? Also would like to get a Mentor if possible

Warehouses require Iron, which you may not have yet until you start building into your Villages. I recommend upgrading your main building more and that will give you space. You can also adjust the space you do have to accommodate for what you need more of.