You've picked a good model to start scratch building. It builds great and flies great. Just be sure to build it straight, which isn't too hard to do and to keep it light. Don't know what you intend to use for power, but I fly mine with an OS 1.08, mainly because I let it get too heavy at fifteen pounds. If you keep the weight at around 12 pounds and use a .90 two stroke or 1.20 four stroke, you'll have a delightful airplane. If you've never cut wing ribs, this airplane, with a flat bottom air foil is perfect. I would cut two templates from 1/8 ply, lite or regular, and drill two 1/4 inch holes, one toward the front and the other to the rear. Cut your blank balsa ribs, match the flat bottom and cut a hole, using a sharpened piece of brass tubing with an outside diameter of 1/4 inch. This gives a better hole than a drill does. After all the blanks are cut, place them between the two templates, held together with 1/4 dowels. Now you can start carving the top, since the bottom is already done. When you get close to the templates, start sanding. Be careful not to sand into the templates. I always use a black magic marker on my templates, and when I see some of the black sanding away, I know I'm done.
Use a disc sander or a razor saw to cut the leading and trailing edges.

Good luck!