There is no such thing as "basic" DnD. There are different editions with different rules, which is what I meant by "system". I need to know which edition, DnD or otherwise, before I can learn the rules. First and Advanced are probably out, but 3.5 is still popular. I'm familiar with Fourth, which is believed by most gamers to be shit, and fifth (aka "DnD Next") is either just out or in public beta, and I'm unfamiliar with that yet (and there are no interesting expansions). There's also the ever-popular Pathfinder, which is a different brand name but developed which permission directly from DnD 3.5,
and has a shit-tonne of easily accessible character, race, creature, equipment etc expansions. I know the character creation and advancement for pathfinder, but not yet how gameplay really functions.
The reason I say I'd have to get a look at the system first is that it's fine to have players who are learning while they play, but truly shit to have a DM who's doing the same. You don't want to forget or misinterpret a rule and make your encounters too easy or impossible, or misunderstand the level system and mismatch the monsters. The first sessions are usually practice anyway, using pre-made campaigns. New players will appreciate the opportunity to change or replace their characters if they don't play as expected.