What you need is: two matching fabrics, thread, padding and temporary adhesiv.
The patern consists of a circle (mine circle had a diameter of 20 cm/8,9" and a rectangle. The short side od the rectangle corresponds with the hight od the future sleeve and the lenght with the product: diameter x 3,14. In my case 28cm x 62,8 cm /10,8" x 25,12"
Cut the fabrics and the padding, temporary more broadly, past the three layers (fabric, padding, fabric) with the adhesive and quilt it.
When finished with quilting cut the two parts in definitive form.
On the shorter side of the rectangle cut out the padding cca 1,5 cm and sew on mashine one layer of fabric.
Fasten the circle to the cylinder first with pins and then stitch them.