Bowyering is the the crafting of bows.
As of current, you can only make flatbows. To do so, you need to carve a flatbow stave using a large branch through the woodworking skill.
First, carve the branch and then carve weapon flatbow, then you must acquire a bowstring of some kind. You can use sinew for this by twisting the sinew via twist sinew and may be able to find other sources for a bowstring.
Finally, hold the stave and the twisted sinew, then use the attach command to string your bow.