To assign buttons to your skin, select the Main image in the Image Selector. Select the button you wish to set up in the Item Selector (below the Image Selector). Use the mouse to click on the upper left of your button and drag the mouse (holding the mouse button down) to the lower right of you button. This will create a selection, or bounding, box. This bounding box can be fine tuned using the mouse on the small black 'grab' squares, or by adjusting the corner values in the Position Selector. Each item in the Item Selector must have a selection. If you do not need certain items in you skin, simply make a 1x1 box for it in a transparent or dark area.