How to create simulations in FDTD?

I want to measure the reflectance data of a silicon wafer imprinted with a grating pattern. For this I want to run a simulation but I am not able to change the parameters of the grating and analyze the reflection data.
Could you help me with this software by giving some suggestions. I really look forward to it.

Thank you.

Dear @harsh.choudhary2

This is a very generic question and I do not know what exactly the problem is. Do you mean that you can not modify them? One thing that comes to my mind is maybe your geometry is set from the scripts under model (which can be found under Objects Tree). In this case software will not allow you to modify them from their edit tab.

If you are new to the software, you can take a look at getting started examples and watch our webinars.

Also, you can take a look at grating coupler example that might be similar to what you want to achieve.

If you still had a problem, please clarify the problem and provide references, and I will be glad to take a look at your simulation file.