These specific photos are geared toward the Whittingham Wrap, but the same principles apply to attaching the edging to Issa's Bloomers, the main (and very important) difference being that when attaching the edging to the bloomers, you'll need to purl the stitch from the lace edging together with two stitches from the main body instead of one. That means you'll be purling three together.
So here's how it's done:
Cast on and work your lace edging as instructed in the pattern. Work a wrong side row of the lace edging pattern to the last stitch.
Purl the stitch from the lace edging together with the first stitch from the main body of the work, joining the edging to the body stitches. Remember, if you're making Issa's Bloomers, be sure to purl the last edging stitch together with the first two body stitches, meaning you're purling three together.
After joining the first stitch, turn your work to work the right side of the lace edging. Be sure to slip your first stitch as if to purl with the yarn in back.
Continue in the same manner until all the live stitches have been joined. If you're working on Whittingham, you'll eventually get to a corner where you'll need to start picking up stitches purl wise before you can join. In part 2 of this tutorial I'll show you how to do just that, so be sure to check back here later in the week.
The patterns that use this technique: