Typically people use dwarf pomegranates and train them to be bonsai trees because the height of dwarf varieties is usually no more than 2-3 feet - also, it might be easier for you to work with as a beginner. That is just an F.Y.I. and something you may want to consider.
I was, however, able to find you a tutorial online on how to create a bonsai from a pomegranate from the early beginning stages:
You can propagate pomegranate trees from seeds or from semi-hardwood/hardwood cuttings. Just keep in mind that this is a slow method to cultivate a bonsai because it normally takes 3-5 years before a tree can be trained.
Here is an article that will tell you how to start a pomegranate tree from seed:
Here is an article that will tell you how to root a hardwood cutting:
The Gardening Know How website has several articles on the general care of bonsai here which can be found here: