MG may not be the best, but it will work despite what people say. Its a little high on N and a bit slow to drain, so lighten it up with about 30-40% perlite. If not, get any brand of high quality potting soil and you will do fine. Add some perlite. This is not nearly as complicated as some seem to make it. Start out simple just like if you were growing any other flower or vegetable. You can always experiment with "designer" nutes and other additives later.

good luck