Welcome to the Guild GE! You're in good company here, many of us started out here as DM's seeking to make maps for our campaigns. Course then many of us caught the bug and kept making maps just for the fun of it. There are some great PS map-making walk through's in the the tutorials section. Best thing to do to start off with is choose one, begin working your way through it, and throw up a map WIP in the appropriate forum and you'll receive some good feedback from experienced members of the Guild. Well, look forward to seeing your first work.