I don't have your frame, so don't even know if what I am about to describe will work for you. I do have a Nolting longarm with a frame. I load the backing first by pinning it to the leaders. I use those big corsage pins. Then I load the batting with about half the amount of pins that I used for the backing. then I lay the pieced quilt top on that, making sure I keep it straight across, then pin it and then baste it to the backing, removing the pins as I go. The original pins for the backing stay attached to the leaders. As I move down the quilt, I baste the sides to keep them from shifting. My backings are always at least an extra 3 to 4 inches larger on each side. My battings are at least 2 extra inches on each side.
Edited to add: I used the search criteria... Loading a quilt on a qzone quilt frame. I watched
"part" of a video on your machine.
https://www.bing.com/videos/search?q...9532&FORM=VIRE
You don't have leaders, but you do have a bar across the back. I would place my backing on the frame first, attaching to that bar in the back. Then I would put my batting on the backing and baste it in place. Then I would add the pieced top. This way you are not dealing with trying to keep 3 layers straight when everything wants to slide and move. Having your backing larger will really help in this process. I keep the fabric trimmings from the backings and use in other quilts.