I thought loading a quilt would be a daunting task, but now it takes me maybe 15-20 minutes to load all the pieces. It depends on the position of your bars as to how you do it. I have a a Grace Inspira frame. The backing rollers are on top and the quilt top roller beneath. I have a batting roller which I never use.

I pin the bottom of the backing first. That is pinned on to what I guess you would call the belly bar. I use flower head pins because they are sharp and flexible. I throw my backing piece over the take up roller, and smooth it out. Then I roll the backing on to the belly bar until the top end of the backing is hanging down the same amount ( about 8") as my short leader on the take up reel. Then I make sure they are even , and pin the top of the backing to the short leader, then I roll the slack up on the take up reel til there is about 2" of leader showing. I'm softening my batting in the dryer while I do this. Then I take my top, center it over the rolled up backing , pin the bottom to the lower leader, and roll it on to that bar until the top of it is about 2" below where the backing is pinned. I float this end, but let it drop back down while I position my batting.. Then I take my fluffed up batting out of the dryer, fold it into large accordion folds along the width, place one end of it over the backing straighten, smooth and let the accordion folds fall to the floor behind the reel that the quilt top is on. Then I pull my quilt top into position baste and away I go.

That's the down and dirty story of how I do it!

One thing I found is how important it is to have your backing square on each end. The ends that you are pinning need to be perfectly parallel to each other or the backing will not be tight on one side of the width. A lot of people will mount their backing so they are pinning the selvedge edges to the leaders. You have the best chance of getting the ends perfectly parallel to each other if you do this. Otherwise you have to do some magic with the rotary cutter to make sure the ends are perfectly parallel, or your backing will not roll up tight on one side. If this happens to me, I just take tucks in the baggy part and pin the tucks till the backing is equally tight across the width of the backing. This is why they tell you to allow at least 4" extra, I always allow way more than that in case you have to make allowances for things.

Good luck!