To found something is like laying a "foundation" for a building — note the similarity? But instead of a building, you might found a business or a charity, where you establish the groundwork upon which it can grow.
The verb found goes back to the Latin word fundus, meaning "bottom," which in turn led to fundāre, meaning "to lay the bottom of something." If you were to found a library, they might build a statue of you near the entrance. If you're having trouble finding the library, look for a statue with a familiar face.