The pattern I used for my sleeves came from The Tudor Tailor and was adjusted to fit my arms and gown. There are three parts to the sleeves, the top fabric (wool) and inside, velvet (which will be seen when the sleeves are turned back) which goes up to about half way on the upper arm and the rest is made of linen (but I used cotton to keep the bulk down).
First I sewed (WARNING! velvet slips when being machine sewn to another fabric!) the velvet to the cotton and pressed seams open. Then I sewed the bottom edge of the velvet to the bottom edge of the wool and pressed seams open. It was then opened out and folded in half length-ways (so, velvet to velvet, wool to wool) and then sewn along the long edge, but not sleeve cap! The sleeve was then turned the right way round.
When both sleeves were made up, I tacked the sleev caps together before pinning and tacking to the armholes on the gown. This is as far as I have got, but I will sew the sleeves onto the gown and then sew on some binding to neaten the raw edges. I will also put a few stitches in to keep my sleeves turned back.