Hello Saurav,
I supose you have your PhC if not, there are lot of examples in the tutorial downloades after the Optiwave’s instalation. When you have it, you go to the Simulation tab and then click in the ‘PWE band solver Parameters’. There you have to tell the programm if it is a 1D, 2D or 3D PhC. Then you’ve to determine the supercell (if it is periodical and homogeneous by simulating for only one cell its okay (asure you to have well defined the cell. That means, your minimun peridical structure is inside the cell). You also have to tell the programm the number of bands you need to calculate and also the path you want to travel along in the minimun Brillouin Zone (k-vector Path).
After that, just press the ‘run’ button.
Regards,
David.