You have to get the instinct tree to the point where you unlock the skill “invade” and then use invade to attack new areas and if you are successful, you claim that part of the world. And as for the secret gardens I don’t understand what you mean.
secret gardens is the area on the mountains to the very left of your screen in the starting place, you can find it right away, so I think you mean something else?
you explore in an area by clicking the button “explore” on the center bottom of the screen and then click a location, and to get to other places you click that eye in the top of the thing at the bottom of the screen where “explore” is
