This is how to do a ribbon spread turnover.
You hold the deck of cards in your hand and you have it slightly beveled. That means you place it like this and you get an angle going towards your hand so you should get an angle like this and you place your index finger over the side. So your third, fourth and fifth fingers are riding along the edge and you have your index finger along this end.
You place it down into a surface and apply even pressure as you go in a straight line or an arc, if you like to do it like this, across the mat. It's important that you just don't try to match the cards because you'll get a very uneven spread that will be very thick at one end. So the important part, once again, is to have the bevel, place your finger over and just spread the cards. To turn them over, you need a surface like this is a closet mat but it also works on a carpet or anything that will have friction. It won't really work on a table so well because it will immediately just flip and the cards won't work.
So what you do is you grab one end and you place your finger on top and you can ride right across turning the entire spread over. This can go back and forth if you like, shuu, shuu, and you can even split it in the middle. So if you go to about the center, place the other finger on top, you can make two peaks go back and forth like this.
The danger is that it will split like that occasionally so I usually just do the spread like this and pick them up.
And that's how you do the ribbon spread.