New to D&D plz help

>>51340936
Assuming 5e...

Probably Forgotten Realms. If not, try Greyhawk. I like Eberron though, because I can do what I want with that.

There are no wrong options as far as classes go, unless you're playing 3.5.

Fighter and Rogue are both good for newbies. The basic idea behind them is very simple, but they offer enough options that as the players get more experienced they can start doing their own thing.

The important question here is: What edition are you going to run?

For 5e, the most basic class to play is the Champion Fighter. It was literally designed to be the simplest and easiest class to understand and play, and it actually is pretty strong as well.
In general, the hardest part of learning a character is learning all the spells, so if you want something simple, just stick to the classes that have few spells or none.

As for setting, you can just sort of use a generic medieval setting and not worry too much. You can also use Forgotten Realms, because it's one of the more popular ones and there's a fair amount of decent novels and adventures that can expand the setting for you.

Don't play DnD

>>51340936
For learning the game I'm actually going to recommend Paladin as a starter class. Hardy, lots of just good passive buffs, and a basic enough spell caster for you to get a good understanding of how the spell system works if you want to a real caster later (assuming 5e).

I would recommend not getting bogged down with a setting and starting out with Homebrew McKingdom unless you've got players who know a few settings well enough that they're interested in playing in it.

I'd also recommend playing GURPS tho...