Yeast

So I've done some research online trying to find a good ratio for flour, water/milk, yeast, and sugar. Basically what I found was that the flour:water/milk and sugar:yeast ratio should be 3:1. So I'm theorizing, after looking at many recipes online, that a good recipe for 1 9x5 inch loaf bread should be about 3 cups of flour, 1 cup of water/milk, 2 1/4 teaspoons of yeast, and 6 3/4 teaspoons of sugar. I'm also wondering how much salt and oil would be good for this recipe? Any suggestions and words of advice would be very much appreciated. Thank you!