I started on 1st ed about 8 or so years ago, but have drifted away from the d20 games in favor of the much simplified tristat system, which only uses 2d6, or 2 six sided dice, for those unfamiliar with the 2d6 term.
As for starting, the only thing you really need to do is come up with a character concept and backstory. Bring an assortment of dice ranging from 1d20 (a 20 sided die), a few d6s, percentile dice, 1-2d8s, and a d4 or two.
You can look up basic rules online, and can even do a personality test on the D&D website somewhere that will tell you what alignment you're best suited for.
As for equipment in the game, it really depends on what you're going for, and what edition we're talking. I only really played 1st ed for any extended period of time, and what I've tried of the newer versions, I prefered 3.5 over 4.0, but your mileage may vary. Just create a character and roll with it, that's the best way to have fun. And be a team player. Most tabletop guys are welcoming to newcomers because we just don't see many anymore. They'll likely give you tips and tricks while exchanging stories of past glories or bowing heads in shame as past failures are also recounted.
Also, never, ever touch another gamer's dice without permission. It's a thing with tabletop guys. Most of them, anyway.
However, I'll add to this by answering:
