c5 0-0 Nc6 and Bg4 when White plays Nf3 is the basic setup of developing by pressuring d4. Then the queen can go to c7, or d7 to a4, but also quite often cxd4 cxd4 Qa5+ is played when this disrupts White's setup.
How to play Gruenfeld defence?

I would say even if you don’t know the theory, this opening is all about pressure against the d4 pawn so the moves can sometimes be very logical.
Try the opening out it. I play it regularly and I really enjoy it.
Here is a position. Then black can play c5 to have a pressure to d4.
I almost never play this opening. I think the bishop in g7 is great. Though black gives the center to white, it seems black has a good change to counter. But I don't know how to do.
What is black's plan next?