So, you go to your character page.
What I mean with Power Draw, is one of the main skills over there in the List, where you can assign points.
To use a bow, you must check what difficulty your bow has.
The most basic Short Bow, has a difficulty of one. This means that you must assign one of your points into Power Draw skill to use it.
Also, to be able to hit something later on, (don't expect lots of kills from a low lvl archer) You will have to put points into archery, on the same screen.
Of course, you might wonder how to make your build, so that you won't fail at the "endgame" stage.
Nowadays this is a lot easier than a year ago, you can just respec if you mess up, or whatever.
Regarding builds, I'm not really an archery player, so this is where the Guides section might help you more.