Step 1: Cut both shirts to size
Then I cut the larger shirt (mine was 4XL because I wanted it to be longer) underneath the sleeves. Doing this created a large cylinder which was consequently too large for my body. To make this more appropriately sized, I removed six inches from the side and sewed the wrong sides together to create a smaller cylinder (sadly I do not have photos of this step).
Step 2: Sew on the applique
Using a zig zag stitch, sew the applique onto the skirt. I had some initial difficulty with this, but then changed the size of the zig zag so it was wider. I also used red thread which makes the design pop a bit.