Flip it over = turn it over, like you would for an playing card (ace, jack) in poker or a turtle lying on his back.

The phrase means, "turn it so the bottom side is facing up".

Thank you, Orkhan!

If you flip something, you ​turn it over ​quickly one or more ​times, and if something flips, it ​turns over ​quickly: I flipped the ​book (over) to ​look at the back ​cover. I ​lost my ​place in my ​book when the ​pages flipped over in the ​wind.