The idea is that white will throw his pawns at your g pawn and break open your kingside. You have to combine pressure on the c file (often sacrificing the exchange to break open the king's position) and pressure from the bishop and try and make counterplay against his king which will normally have castled queenside (if they are doing the pawn rush), perhaps throwing your queenside pawns at him.
Ideas behind Sicilian Dragon?

You got to defend accurately in the dragon bcoz white can get a very strong attack following Be3 Qd2 Bh6 h4-h5 ideas and there are some tactical traps for moves like Qa5 by black. For most of the games i've played in chess.com and tournaments, dragon is like a race but white will win if black can't defend actively. I've played against the sicilian dragon in tournaments(otb) 3 times and won all three using the following setup:
e4 Nd4 Nc3 Be3 f3 Bc4 0-0-0 and Qd2 with the h4 ideas.
i don't like the Be2 variation too slow for me
Just develop naturally, with 6...Bg7, 0-0, Nc6, Be6(generally after white's knight retreat to b3 in this line to avoid tactical possibilities based on the pressure on d4) and follow up with Rc8 and try to get some play on the queenside, sometimes with a6 and b5 or Na5(if white exchanges you just activate your queen and you get a comfortable active position otherwise you can play Nc4). Oh, also see if you can get the typical d5 break in, that is an instant equalizer.
By the way, this is known as the Classical Variation when unlike what the first posts said, white is not trying to blow you from the board like he does in the yugoslav attack.
Hello! I'm preparing a line in Sicilian Dragon, but I wonder what are the ideas behind dragon? I play it like other Sicilians, but I don't if it is OK. Where do you need to be careful? WHat are some typical position in it?
My opponent will probably play 6.Be2 7.O-O 8.Be3, so what can I do?
Every comment appreciated! Thanks! :)