Hello Yassine,
to have something to start, I would recommend to have a closer look on the the project data of this AppGallery Article:
https://optics.ansys.com/hc/en-us/articles/9216542212115-Backlight-Unit-Analysis-and-Optimization
The article adresses most of the topics you have mentioned.
In addtion the "Ansys Speos Getting Started Training" on our Ansys Learning HUB and you're able to master your project: (https://jam8.sapjam.com/groups/n6eyR8p8BeUofcheLnuqBL/overview_page/uwVjLWyXRyvOzNFRrIdiNE)
You are navigating away from the AIS Discovery experience