First, using the line tool create a circle, then using the fill tool and the magic wand fill the circle in. Select the circle with the arrow and then go to the tools menu and select stairmaker. (This actually applies to any drawn shape, it doesn't have to be a circle.) I hope that helps. The stairmaker has a variety of parameters that allow you to edit the dimensions and appearance of the stairs which you can play around with until you're satisfied with the stairs. I can't explain all the different parameters right now but it might help if you look at the stairmaker menu with help tags on. I hope this helps.
