Yes, I can do that now. I mean after finishing the installation. During the install I had to learn how to enable encryption. So you can understand that FDE is something which is completely new to me. Despite the fact that I was not aware of the “technical” meaning of passphrase I had guessed what it means & luckily my guess was correct.
Now the only thing that’s causing worry is if I made the right decision of using my login password as my passphrase.