I'll give you some basic pointers for getting started as it took me about four hours of messing around to get anything useful out of the tool. Use the drawing screen in the upper left hand corner to do your map making. Select the free hand selection tool (there are 3 available, circle, square and free hand) from the tool bar and draw a basic outline of your island.
On the upper right are a series of icons, select the one that looks like a paint pallet and click on standard (no need for text). Now set your brush to elevate and make it max diameter in size (200). Click on the center of the map and a big white circle will appear within your hand drawn border. Move the mouse around on the white spot and look at the Z-axis height reading in the lower left hand corner of the screen.
Find a proper height assuming the black is at zero meters or sea level. Now, if there are heights above the height you want select the "flatten" option from the paint menu and click right on the height you want until the entire map is a uniform height above sea level. If the height you want is the highest on the map use the "plateau" option and set the heights to uniform in the same manner.
Now use the free hand selection tool to embellish little details on the map by drawing peninsulas or coves and bays. Make sure it overlaps a painted section of the island and use "plateau" to make a peninsula or to expand the island (click on the painted section and it will fill in your selected area) or use "flatten" to make a bay by reducing the selected are to sea level (make sure the selected area overlaps a portion of the black and click on it!).
Now create a gradient for better viewing of details. Do this by selecting the little colored balloon like option in the upper right hand corner. The color menu will pop up. Select "gradient" and either load a pre-made one or custom make your own. If you make your own it takes a bit of experimenting but its not too hard. Simply click on any part of the gradient between the top and bottom and a little flag will appear there (you can move the flag up and down along the gradient with your mouse and get a percentage reading for it). Right click on the flag and select "change color". A little spectrum will come up and you can select any color you want along it. Click on "change" and the gradient will change to that color where you made the new flag. I recommend a new color around every two percent point increase on the spectrum so you can see small changes in terrain heights on your map. Now make sure there is no highlighted area selected on the map and from the top menu bar choose the "select" drop down menu and click on "select all". Now on the gradient menu on the right hand side of the screen click on "apply to selected area" and then click on "create gradient" (I think thats what its called anyway). Now right click on the name tag of the drawing surface (I can't remeber what its called, but its the gray box with text in it in the upper left of the draw screen) and select the "render color map" option. Your map should now be in color!
Now use your free hand tool to outline an area for a mountain or hill and paint in the mountain within it by selecting the "elevate" option from the paint menu and filling in your selected area. I recommend a brush setting of size 8 and a brush depth of 4 to 8 for doing this as it gives you more control. You can use this to make lakes and river by highlighting the selected area with the free hand tool and painting in it with the "lower" option on the paint menu. Pick a suitable depth and use the "flatten" option to make the entire highlighted are a uniform depth.
Keep your new mountain highlighted within the selection area and choose the tool on the upper right that looks like a pickaxe. Select the "erode" option, customize the erode tool to your liking by using the slider bars and click on "apply filter". Your mountain will now be eroded to a more natural look.
Now click on the little grid option in the upper right tool menu and select "planar". Click on "create grid" and voila! You've got a 3D view of your map and mountain to see what shape it will have in wrp edit. You can use the manipulate tool from the top menu to move it around and see it from all angles.
Just keep messing around with everything to see what it does and you will soon see that this program beats the cr@p out of Wilbur! I still use Wilbur to do fine adjustments on the map as it has a finer paintbrush setting for applying heights and you can apply layers down to 1 meter which you cant really do so well with Geofrac. Also I like Wilbur's smooth tool better for making final last minute adjustments to hills and mountains before I export the map to wrp edit. I also use it to save the map as a lat/lon mesh. Geofrac exports its files as a terragen file, so if you want to look at it in Wilbur, export is as a terragen and open it up as a terragen in Wilbur to have a look.
You can use the square selection tool to highlight and manipulate an area of one pixel in Geofrac whereas in Wilbur you can only alter a minimum of a 3X3 area.
I'll get going on a full tutorial when I finish my new Mekong delta map, hopefully by next weekend.
Have Fun!