Hello! I am tryign to create a cave using the CaveEpic set under Mines. the problem I see is... where is the floor? Am I supposed to rotate pieces to make a floor?

There's probably a floor piece in one of the other categories. That should work fine

I'm also having the same issue. Just created a cave epic room and went to lastly create a floor with the only mid piece but it is a ceiling tile.
Did you find a floor tile for it in the end or improvise?

Turns out for a very basic floor but one which fits nicely with the CaveGCliffs is CaveGFloor01. I'm hoping once I fill in this enormous space with pillars, boulders, cliffs etc it will look more organic.