These are basically rectangles that go from the bottom back up and around to the bottom front, with smaller triangle "wings" to protect the arms.
I measured and cut each section (3 per piece of furniture), and made quilt sandwiches with flannel on the back. I did overall meandering on all the pieces, measured and fitted again, then joined the side pieces to the main sections. I then added matching binding all around the perimeter, machine stitching it to the front, with a decorative stitch.
I used a spiral upholstery pin here in there to keep them in place, especially where the arms curve under.
Everyone is happy and the dogs love them!