Hi Fatemeh Mostafavi ,
The following page discusses the migration of Lumerical technical resources:
https://forum.ansys.com/discussion/25174/where-can-i-find-lumericals-technical-resources#latest
You mentioned about downloading a prepared example of FDTD from 'the website', but which site are you referencing? Please review the above post, which I hope may address your questions on Lumerical.
Please note that this forum is for Discovery family of products, not Lumerical, so if you need further assistance, I suggest that you post a question on the Ansys Learning Forum, not here.
Thank you for your understanding,
Sheldon
You are navigating away from the AIS Discovery experience