The Polygon tool allows you to draw a polygon. Simply click and hold down the mouse, drag until you get the size polygon you want, then release the mouse button.
The stroke width option the thickness of the polygon border, while the current Stroke Color will be used for the color of the polygon's border. The Number of Sides option lets you set how many sides you want the polygon to have (up to 10 sides).
Elements drawn with the Polygon tool can be filled with either a solid color or a gradient. You can also apply a drop shadow to polygon elements, as well as bevel/emboss them, or add a glow to it.