I don't know if this will be a lot of help. but you can (just about) see the process involved in making a polygon in GE in
this video.
What you want is a
Polygon - start a new one by clicking on the icon in the toolbar:
Just make sure to click "OK" at the end, in the accompanying window that opens when you start drawing the polygon - otherwise you can lose the lot, and there is no "undo" in GE!!