This is an old revision of the document!
You'll of course need inkscape installed
You'll need an image. .png's work, probably other formats too. It should be as straight as possible. Use a tool like the Gimp to correct rotation if necessary. It should be straight enough so that a line from top/bottom or left/right is straight enough for your purposes.
This assumes that you have a 90 degree routed sample. You'll have to make tweaks but nothing major for something not of that nature.
I am as of the time of this writing us a mix of Inkscape 0.47 and 0.48.
Launch Inkscape and lets get started
Edit ⇒ Preferences
Without this every time you create a new polygon you'll have to keep re-selecting things.
And save it somewhere.
File ⇒ Document Preferences
Without this it will be difficult to get polygons to line up predictably.