How to play D&D in a nutshell: learn to do quick math to roll as many d6 or d8 for damage as you can, use
The Gamers films as source material and bribe all the table (not only the DM) with food & drinks. Jokes aside, there are essentially three kind of groups for any roleplaying game: those who gather because they enjoy building up stories together, those who want to play a complex tabletop system inspired by videogames and those who do that as a friends group activity. Know which of them you'll be joining to and you'll learn the answer, not that it'll save you from meeting a significant amount of toxic players that only know how to have fun by giving others a hard time (it also applies to DMs of course).
As for editions, first edition (BECMI, AD&D, Old School Essentials, Dungeon Crawling Classics) is the simplest mechanical way to play (and the most rewarding), second edition is both for Beamdog nostalgics and rarely for old modules players (it's half old school and half third edition), third edition had the first mess of Wizard of the Coast because they only wanted more rulebooks to sell and players ended up switching to Pathfinder progressively (it was preferred playing 3rd/3.5E adventures with Pathfinder), fourth edition was an entirely combat focused system poorly executed and fifth edition was a great recycling scheme that used fourth edition as a base and brought back some things from the past to make it look presentable (though it's poorly written, both system and official adventures). 5.5 (or D&D5 Next) is nothing else than D&D5 fan service.
My tip? Read classical literature and start playing something other than D&D (at least as the first roleplaying game).