1. have you left-clicked and dragged on that square on your top image (the crosshair with elliptical circle on it with two dots, and arrow pointing down)

that is your pen nib, click and drag on that square to get the arrow to point in the direction you wish to use the brush, useful for caligraphy brushes.

2. i think rotation is to actually rotate the brush as you are using it, so a bit like an electric toothbrush, may give swirly effects, but i haven't tried it. and i think the tilt part is the responsiveness to pressure if using your wacom pen at an angle, again not sure though.

3. see answer to 1)

4. oops there is no question 4!!