Here's my take:

1. Only get the Basic Rules (free online) and roll with that to start. Don't put money into it, yet. Avoid optimization questions, avoid complex classes (Sorc, for instance). Try and keep it simple.
2. Pick a short adventure of your own design--avoid the modules (both official and unofficial) for the start. Think of a fun action or adventure film (that isn't fantasy) and adapt that plot and structure to a fantasy world. So, for example, someone in the party has a nemesis and is the ruler or governor of a small city, and the party is out to devise and execute a way to steal the tax money that's closely guarded and collected and put into the stronghold--and they have to get away clean; they just need the right specialists in the party for the job (Ocean's Eleven). OR (one of my favorites to do for new players), everyone is young and orphans that have grown up on an estate with a patron that's taken them in over the years and fed and taught them a trade (background) or a real specialized job around the large ranch/farm/estate (class); a neighboring land baron comes in, kills him, and is working to acquire his lands and the party gets to go seek revenge on that baron and his minions and stop him (Young Guns). I suggest things like this, because they can be perfect, minor dramatic (offering rich RP opportunity and character building) moments, with a real regular drop of action beats and combat whenever you want. No special monsters (maybe some low-weird one or two like Bugbears or Orcs, but no Aboleths or anything). Just drama, action, adventure, win. This will give everyone a taste for D&D and system and what they might want to do in a MORE complex game.
3. Play it all by ear. Run them through a two session (end the first one on a cliffhanger, like way WAY too many guards/minions riding over the far hill toward them), let them try and solve problems cleverly (the PC that magically blows up the outhouse while a henchman is relieving themselves; the barbarian that distracts half the town guard to lower the diff for Sneaking into the stronghold; etc). When they accomplish a significant clever thing, give them a scene of dramatic interest (NPC's praising them, a planning scene for the next leg, etc.) or an action scene. Keep driving it forward.
4. Rules are only there to make the game work. If the game is working, the rules are working. Have a mechanism to quickly decide things in conflict. Start with (A) the DM is just right (and there should not be any argument on a ruling) and (B) the DM may elect, when he doesn't know, to toss a dice and on high numbers the ruling is X and on low numbers the ruling is Y and The game keeps moving forward, we'll read up on it all after