I usually trace the rib from the plan onto thin, white paper. Cut that out and use it to make a template out of plywood. Then I use the plywood template to cut out the ribs. That's for a constant-chord wing. Your ribs will all be identical, except for a few that may have additional cutouts or may have a differing thickness of material. Check the plans. The differences are usually not critical, unless one or two ribs have to be made of plywood. If you are careful, you can cut out plywood ribs with a coping saw and then sand to final contour.

You can make an entire airplane out of hand tools if you desire. Power tools only make it easier and faster to mess things up (or do them well-you pick!)