I'm a novice, just to explain my experience. 

Looking to add the following SSD to my system: Crucial P5 2000GB PCIe M.2 2280SS SSD

This is the first SSD on this system. I have come to realize my FlexBays are not set-up for it mechanically (as in not wired or have the internal parts, I did buy a Flexbay that could hold it, but it does not read the card). After researching this issue for a while I determined that path was beyond me. 

My belief then has been that if the card with an PCIe adapter in one of the open slots, that this approach should prove simple (it's what all the videos on it say, any how). 

I have tried 2: 

Sabrent NVMe M.2 SSD to PCIe X16/X8/X4 Card with Aluminum Heat Sink (EC-PCIE) 

Dual M.2 PCIE Adapter for SATA or PCIE NVMe SSD with Advanced Heat Sink Solution,M.2 SSD NVME (m Key) and SATA (b Key) 22110 2280 2260 2242 2230to PCI 

Both have the result of the computer cycling into the 'repair' screens and never really repairing. I can only get the computer to boot by removing the card. I've tried both in a few slots. 

I'm sure there is something about Bios or something that I don't have set-up or know. Any thoughts or ideas where I'm going wrong appreciated!