Backroll to revert (off the water)

Hey guys so I'm really gonna go for a backroll to re this weekend. So just to make sure I understand it correctly...so when the line gets tight around the corner cut under the cable, then start my edge at about 50 and when I throw the trick cut really hard and throw my front leg out as if I'm trying to throw it behind my head, then extend off my back foot(I know it's not a ollie) and tuck my head to my back shoulder while letting go off my front hand?
Thanks!

You won't be throwing the front leg. When you edge the board hard the water will grab the board and throw it up into the air. That particular aspect of the board launching is automatic and the result of a hard edge away from the cable. When you edge away from the cable push your trailing leg into the water. It's sort of like standing tall on the wake. You aren't jumping but increasing the pressure of the board against the water.

If there is anything you need to think about it's getting a death grip on the handle for your initial attempts. The rebound of the cable as it pulls you up and forward generates a lot more force on the handle than a roll behind the boat. Also turn your head in the direction of the roll. No conscious attempt at tucking involved. Release the forward hand when you are halfway through the roll.

Whenever I edge really hard I never feel the water grab my board. Do you have to push down on the front for the water to grab it?

You need to fall into the edge hard. If you edge hard and build up speed then you will lose edge. Just take an easy edge and when you want to launch lay hard into it and carve the board away from the cable quickly. The rest will happen practically by itself. Many people do edge hard and build up speed, but they already know the technique to initiate the launch. My recommendation will make it easier to initiate the launch. After that you can work on better technique.