1. FH folder (where all FH files are stored) is default at the main drive (mostly C: ). You can get there by clicking start>my computer>C: .
2. You'll see when you are there.
3. a) you'll see, lol. b) rightclick on the heightmap (png image file) and choose copy in the menu that opens. Go back to the terrains folder, rightclick again, choose paste. c) rightclick your copied heightmap again, choose rename. Then enter the new name for the heightmap. d) Open gimp, drag the heightmap into the window.