File Vault - what do I have to do to make it work

Hi everyone, need help. Can you tell me please how to activate File Vault on Big Sur, do I need some special kexts or anything ? I remember last time when I turned this encryption on in Success' href='/2020/12/install-macos-catalina-on-supported-pc.html'>Catalina system did not boot and just wonder if there is the same problem in Big Sur.
What do I have to do to make it work.
I have system on OpenCore, NVME M.2, APFS partition.