MNblockhead
A Title Much Cooler Than Anything on the Old Site
I disagree about the Dungeon Master’s Guide. The 5e DMG is really not a guide for dungeon masters. It’s a pile of optional rules.
That describes very little of the DMG. One can argue on how useful the DMG is for a helping a new DM understand how to run the game, but a large portion of the book is advice on how to structure adventures and campaigns.
A more easily digestible summary of how to run a game is the DM advice in the 1e module Keep on the Borderlands. Goodman Games updated it for 5e but it is unfortunately very expensive. Still, I think getting the original PDF and printing out the section on how to run games is still useful.
That said, I think you could read over the basic rules and watch a couple Chris Perkins live-play videos on You Tube and you'd be off to the races.