1. O.K. here is a way to create 3d looking stairs in only a few steps. With perspective drawing you reach the same goal but it tooks much longer.
2. Create a new document 500 to 500 pixel. Make a new layer and fill this layer with a color of your choice. The color isn't important.
3. Go to Filter-Render-3dTransform. Press M for the Cube Tool and make some drawings like I've done.
4. Press R for the Trackball Tool and Turn them around.
5. Press O.K. and you will get something like this. Easy, right?
6. Press OK and you're ready. After a few times you will get nice results. Good Luck!