Re: Polygon
Polygon pours are used to make irregularly shaped areas of copper on a circuit board. In Altium Designer, you can draw them by drawing the outline, you can make an ouline of "keepout" traces and then pour the copper into the outline, or you can select an outline from objects on the board and pour the copper into the outline.
There is a document in the "Help" subdirectory of your installation that tells you about polygons - take a look at: "AP0101 Polygon Pours and Copper Regions.pdf".