XPS 8920 RAID create

Tried to create RAID 1 from the BIOS. Turned SATA Operation to the RAIDon. Boot is set to UEFI. But when computer starts no screen to create any RAID (usually it is matrix screen). Contacted DELL tech support. No answer. Spent with them more than one hour and understood that they are less knowledgeable than me. Any advice how to do it? I do not want to do it from operation system installing a Rapid Storage Driver because later I might switch to Linux.