There are some great YouTube videos that show how to do it. You can also get some great tutorials from Global Sugar Art and a few other online cake supply stores...sorry I dn't have the links but you can Google just about anything
Working with fondant takes some practice but it's really not hard as you may think. I finally took the plunge in October this year on a Halloween Bday cake I made for a friend.
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It's not perfect but I'm still in a learning phase :)
I've made MMF and have used pre-made...prefer the pre-made 'cause it's already colored, less mess to contend with and I like the texture better. You can add oil-based flavoring to suit you as well. It's really a matter of personal preference but if this is your first time, it might be worth the expense to purchase pre-made. MMF is a bit too stretchy to work with IMHO.
Good luck with your Gran's cake...be sure to post pics
Edited by newbaker55 - 12/29/12 at 3:12pm