Yew is great for a bow, but there is a lot more to it than just the wood. If using one piece of wood it will need to be really long (a long bow). You can make a much shorter and handier bow if you make a laminate from different materials (re-curve). Look up the Hun bow. If you're going really primitive sinew is perfect for string, tying arrow heads (with pine resin), and tying fletchings (also with resin).
Arrows are an art all to themselves.
I was fascinated with making bows and arrows as a kid. That ended when I finally got a compound bow.