You didn't mention any details about your computer setup as to Make & Model of Motherboard, GPU, Drives, CPU nor Windows, AMD Raid and BIOS versions installed.
Found this from ASRock concerning RAID installation. It is most likely out-dated but may still help you find how to enter the RAID ROM Utility:
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For UEFI RAID:
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Seems like from a Google search that each Motherboard manufacturer has it own AMD RAID Guide to install AMD RAID.
I have attached both ASRock PDF and AMD RAID QUICK Guide to this reply for you to view if interested.