Constraining a movement to a rotate

Hi all,

I am interested in rotating an object around a central pivot point, on command from two buttons (a + button, and a - button).

This file would essencially be a clock hand, or dot representing the hand, being rotated either clockwise or counter clockwise manually by a plus and minus button.

Things I am unclear about:

  1. what forms of syntax, variables, etc, would I need to accomplish this task? I am unclear about the proper protocol for setting up this movement.

  2. I have a specific background graphic that all this will be happing on top of, how do I find the desired pivot point coordinates (i am assuming the pivot point is defined by an x and y) in relation to my background graphic? I can point with my finger to the spot, but I dont know how to define the actual point.

Thanks for the help!

Haus