how do i make a ribbon out of fondant? also which works better marshmellow fondant or regular fondant?

I have only used MMF myself. Basically you roll out the fondant, then using a ruler you cut strips to the width and length that you need. If you don't want to do it that way, you can buy a ribbon cutter at Michael's too, eliminating the need for a ruler.

I mix fondant with gumpaste 50/50. Fondant by itself takes too long to dry. I use a quilting grid and cut my strips. Fold and glue the ends to the middle AFTER squeezing the ends. Cut a strip to wrap as the knot and glue around bow. Then cut your strips for the ribbon bows. There is a GREAT video on youtube by toedna that is sooo easy to follow. Give it a try.