From sitting on the catch trap. At the front end, move your hands down slightly. At the backend, slide to your knees. Push your swing up into the front end. At the peak at the backend, move your hands to the bar and as you pass the bottom of the swing, unhook your legs and take them around the outside of the bar and push them back in through the other side. Hook your knees over the cables. Once you reach the backend, take your hands off and you are ready for the catch.
You can find out more about this trick in my books:
Thanks to Jessica and Ryen for providing videos for this page.