Design and simulate a 2D crystal lattice

Dear Materials studio users, 

I'm new to the software. I need to build up and simulate the characteristics of a 2D COF i.e. XRD pattern. I've watched some related tutorials but they required lattice parameters and space group and the only thing I have is a ChemDraw sketch. Then, how to design a 2D crystal lattice with unknown lattice parameters and coordinates? 

Many thanks in advance.