You prepare the sinew by pounding the sinew betweem two smooth surfaces. Use a big smooth rock and a smaller round fist size rock. I feel like a darn caveman. I rotate or roll the sinew as I pound it that way the whole thing gets worked pretty good. At some point the outer sheath will come off. Then you can just start pulling and separating the pieces. It will work your hands pretty hard. These days I dont go very fine with it, about the diameter of a BB.
You will use 5-6 average tendons on a bow.
Just before use soak the sinew in warm water and it will relax and get very workable. Pull a piece from the water squeeze out the excess water, put it in the glue squeeze out the excess glue then lay flat on back of the bow. I work each piece out from the center with my fingers in both directions at once to make sure it is laying straight and has some tension on it. As it dries it will shrink and become very tough. Put it on in layers, laying the strands end to end. On the next layer make center of the strands cover the place where the previous layer butted together. Like laying brick.
Hope this helps,
Mark