I have read past threads but still have doubts.

I backup to a secondary drive called /backupdrive on daily, weekly and monthly basis. If I do an OS Restore, what is the correct way to restore the contents?

Can I restore all installations such as APF, BFD, Chkrootkit etc?

What is "Restore a Full Backup/cpmove file" for?

What are the things I must do before I start "Restore Backups" for each account?

After the OS Reload, the first thing I should restore is "Configuration File Rollback"???

The cPanel backup system backs up all your account data (files, databases, emails, etc.) and some system config files - that is it. After a system reload, it is a good idea to do a fresh install of the latest software you are using like APF for example.

Restore a full Backup/cpmove file is usually used if you want to restore an account backup that is not stored on your backup drive (for example, you have transfered a cpanel backup from another remote server).

Before you start restoring, make sure the server is secure and optimized. That way, once you start restoring accounts they will come back online and everything is set to go.

Configuration file rollback restores some basic configuration files such as exim, fstab, httpd, mysql, etc. I believe.

Thank you for the explanation.