Im not an expert on things like that but as far as I remember you have to make your cloth shape. Then goto cloth --> Create garment.
Then you go into the Inputs and play around with the solver scale and gravety. etc.
Make sure you creat a collision object on your character.
Finaly goto Simulation ---> Start simulation and it all should work sort of to plan.
Of course there is more you have to do and some figures to play around with to get the look you want but that should be a good start.
Hope this worked, tell me if it doesn't