This is a good tutorial, there is another one on youtube that is pretty good, but this lady explains her folds better. Offray.com also has some written instructions on how to make the roses. It takes practice and the hardest part is getting the first little center folded, I call it twirled, or just tightly turning the ribbon into a tiny little center. Then you start the folds. It is better to make your folds at a sharper angle down for a better petal. Or if your ribbon folds into a long piece, just turn your rose and fold it down again. I know I can never explain things to people, I don't know why I try!
But I am left handed and everything is backwards to me and if I can do it, anyone can. Just keep practicing.