I changed the order of instructions. The pattern has you sew the under and upper seams of the sleeves before attaching to the body of the jacket. I decided to just sew the under seam and then attach to the body. This way I could pin fit the sleeves to the shape of my shoulders.
To help reduce the extra fabric in the back of the sleeve that I had in the muslin, I pinned the seam of the sleeve a little bit deeper.
I also sewed up the matching skirt today but still need to hem it. I will post about that another day. But here is a picture of the top of the skirt with the matching binding on the inside of the jacket.