I LOVE working with ganache. It is a little more time consuming, but the result is beautiful!!
Warm the ganache to a spreadable state. (you may need to do this several times in the course of icing one cake, just depends on how quickly you spread it.)
Spread as evenly and smoothly as you can get it.
Chill for about 5-10 mins.
After it is chilled use a hot knife to smooth even more.
Chill again for 5-10 mins.
Next take hot water and a pastry brush and "paint" it smooth with the hot water.
You are now ready to apply fondant. Brush with a little water to help the fondant adhere. Apply fondant the same way you would over buttercream.
If you have any more questions feel free to message me.