Drawing a Bow - Before a bow can be aimed or fired, and after it has been loaded (i.e. after the the arrow is knocked) it must be drawn. This action requires one hit point or hit points equal to the bow's pull minus the character's size, whichever is greater. Your reach must also meet or exceed the bow's minimum reach requirement.
Releasing the Bow - Releasing the bow without firing the arrow is a one hit point action.
Drawing a Bow Half Way - If your reach is at least half the bow's reach you can draw it halfway instead of drawing it normally. This requires half as many hit points, or one hit point, whichever is greater. The bow fired this way has one fourth of the normal range and has 2 points less attack power.
Drawing a Bow the Hard Way - By sitting down to draw the bow, you can use 3/4 of your length instead of reach, and you can draw the bow with half as many hit points. While the bow is drawn you are actually in a lying down position, and you can't do any action except keep the bow drawn, release the bow, or fire.
Keeping a bow drawn - Once a bow is drawn you can keep it drawn for the rest of the round. To keep the bow drawn each following round until it is released or fired, you must use hit points equal to the bow's keep-drawn cost minus your size, or zero hit points if your size is greater. The keep-drawn cost is the same as pull for normal bows. Compound bows have a lower keep-drawn cost. You don't have to use any hit points to keep a crossbow drawn.
Crossbow Drawing Tools - A tool can reduce the hit points needed to pull a crossbow by splitting it into multiple steps. A simple lever can reduce the hit point requirement by 2 points, but requires 2 actions instead of 1. A crank that requires 3 actions instead of 1 reduces the hit point requirement by 3 points. A 4 action crank reduces the requirement by 4; a 6 action crank reduces the requirement by 5; a 8 action crank reduces the requirement by 6; and so on. (Doubling the actions reduces the requirements by 2.) Each action uses one hit point.