Jake gives some excellent advice; listen to the man! I'd just like to add that it may be easier on you if you do a short scenario or two, first, rather than jumping into a full-fledged campaign. For example, sit with your friends and their characters, put some orcs on a map, and have a battle-for-no-good-reason to test out combat mechanics. Sit around the table with some drinks and try role-playing a meeting with a king. Pull up a random map and discuss traveling in a caravan from town to village to city. Stuff like that. Small bites at first, get the hang of things. I GM Pathfinder, so I'm not sure about 5e, but I'm guessing they have something similar... Paizo publishes very short modules to be used in one session, for conventions and the like. The nice thing about these is that they are small enough to be finished in one or two sessions, but complete enough to feel like a 'real' game. Look for something like this to start with, so you don't burn out or find yourself thinking you've made a fatal mistake. And make mistakes, 'cuz that's how you learn. -Phnord, of the many mistakes, and advice of questionable validity.
