Are you new to D&D in general, or just to being the DM?
Have any of your friends played before? Having at least one experienced player in your group can make DMing a lot easier. If none of your friends have played before, do you know anybody else who has that you could invite along (and maybe make a new friend)?
Otherwise, I think the best way to learn how to DM is to jump in and do it, and not worry if you make mistakes. There's no "correct" way to DM. Develop your own style, find what works for you and your players, and leave out what doesn't.
