I "came"up with a way,(maybe had it in the back of my mind from someone else, too old to get it right!). First, make sure that all pieces of top will fit together (are same size so as not to wrinkle or bunch when joined together later. I join a couple rows together, sandwich with batting and backing larger than rows. You can fold backing over batting and pin to make smaller. Quilt up to about 3" from all top edges, then add another two rows to top, add more batting behind it, (I iron tape or interfacing to batting to attach) and then add more backing with about a 3/8" or 1/2" seam. Do each layer separately. Then sandwich that part making sure there are no wrinkles. Quilt that part up to about 3", etc. You will only be working on the parts that you attach. The bulk will be on your left and that way you do not need to manuver a heavy, large part under the harp, and you don't have to add any strips between blocks to attach or sew thru quilt, batting and backing to attach, which sometimes makes wrinkles or bulges. You can start in the middle with a few squares, or do rows across. Start with a small quilt til you get the idea and then look out, you will be addicted to finishing projects this way!
Hope I explained that well. Sometimes I have trouble putting into words what is in my head.