The main thing you need to know about a power drill is that you can swap out the bits (head ends). Most modern power drills tighten by leverage. Here’s how it works:
The power drill has two other important components. There’s a button, near the trigger, that tells the drill whether to go forward (clockwise) or backward. There’s also (in most drills) a torque setting. When torque is set to its lowest (loosest) setting, it will tighten the screw until it feels a little tension, then start clicking rapidly. When torque is on its highest setting, it will keep tightening the screw until it cams out (see the screwdriver article, if you forgot what this means) or until something bad happens (strips the screw, pokes your eye out, etc.). Usually, you should start with a low to medium torque setting. Then, if you need more, adjust accordingly.