To begin simply roll out the fondant as thin as you can. I'm using Via Roma Bakery Fondant on this cookie, but any kind will work. The only advantage of the Via Roma is that you can roll it extremely thin, and it stays soft for a long time.
After you roll out the fondant, cut off the ragged edges using an x-acto knife, and then slice into strips. The size and length of the strips will vary depending on how large you want the finished rose to be. I cut my strips short and narrow because these roses were going on small, round cookies. And don't worry about getting the strips even and uniform. Remember - there are no straight lines in nature.
To start the rose, just start rolling up the strip of fondant...
When the strip of fondant runs out, just fold the trailing edge down toward the base of the rose.
All that rolling and crimping will give the rose a large, bulky base, so just cut it off with a scissors. But be careful that you don't distort the shape of the rose as you cut. If my fondant rose is too soft to handle I will set it aside for a few minutes and allow it to firm up before I attempt to cut it.
After the cut...
And that is all there is to making a fondant ribbon rose. In a few minutes you will have enough to decorate dozens of cookies.