GingerK

First of all, what type of fabric are you using for your window covering--the background that is. If all your fabric will be cotton, I had very good luck with using the 'freezer paper-spray starch-machine applique' method. This method produces an applique piece similar to needle turn. Mr. Google will bring up multiple YouTube tutorials if you enter those parameters.

DO NOT and I will repeat DO NOT use Heat H Bond Ultra. It has its place for sticking down stuff that will not be sewn down, but does not play at all well with sewing machine needles. Think sewing thru duck tape.

Wonder Under and Steam a Seam work well if you are planning on raw edge applique. You do not need to stick down a whole large piece. In fact some applique patterns suggest drawing the outline of the piece and then cutting out the center to be used for other pieces.

I am attaching two photos, each done with the freezer paper method. The first is curtains that I made for DGD (that is where I fell foul of the dreaded Heat N Bond and had to rethink the project. The second is a baby quilt.