How do s hit on each other? how to know how to make the first move....?

If you're in a gay club, and you see a girl you find attractive, give her a smile. If she smiles back, strike up a conversation. Of course not everyone in a gay club is gay, but no one is going to punch you in the face for uming they are! That's the nice thing about queer spaces, you get to escape heteronormativity for just a little while. You get to ume everyone is queer, until they say otherwise. Just go for whoever you think is cute and take it from there! Good luck.