The book you refer to has several different techniques. With most of them, you QAYG with sections of the top. Since you have already finished the top, most of these techniques can't be used. I think there's probably only one method that will work: split the batting in thirds. You can split the backing in thirds too, or leave it whole. Sandwich the center of the quilt & quilt that to within an inch or so of the edge of the batting. Join the next third of the batting using fusible batting tape or stitching the pieces together. If you have split your backing, join that too. Sandwich this section & quilt. Repeat for the other side.
Before I got my longarm, I used a couple different techniques with good results.