Like, how do you aim it?

The generic and basic ones you might have to sit in a slightly different position depending on where you sit, but the more expensive ones have an arm that you can move forward or backward to aim where you need it. I use it almost all the way forward, husband uses it most of the way back.

How do you dry off?

Ours has a fan - you can adjust how warm the air is and how hard it blows (I don't like it too warm because it feels like it burns my asshole). You use the fan to get as dry as you want to - a lot like the machines that dry your hands at public restrooms, actually. When you're done, you're either dry enough to pull up your pants and wash your hands, or you use a lot less tp to dry the last few droplets.