The photos show the progression of the process as I'm sewing two charms together. To begin you just line up the upper left angled edge of the charms with the gray diagonal line and the point of the charms to the gray line on the bottom and follow that line as you sew. You can flip the charm around to complete your second seam.
The cling comes as one large piece and you can choose to cut out a small area where the needles and feed dogs are or a larger area around the free arm like I did. You can see above and below here that I did put a piece of quilters tape across the arm of the machine to extend the gray sewing line so that I had a precise line for the entire seam...otherwise the last inch or so you have to eyeball it. (My first ones ended a bit crooked!)
Overall it was a pretty quick process to sew these charms together and I was happy with the Clearly Perfect Angles tool. Time will tell how well the cling holds up...so I'll keep you updated on how it lasts.
Now the fun begins, pressing and trimming!