Hi folks, not a question, but rather I wanted to document something to help out other users who might get into this situation too. I recently got ahold of this notebook computer, the Acer Travelmate X314-51-M and it arrived to me used, without a storage device installed. No problem, I have experience getting notebook computers up and running. Bought an M.2 NMVe PCIe Gen 4x4 device off of an online shopping site, got ahold of it, and installed it in the drive bay. Powered up the system, and the BIOS couldn't see it.
Turns out, HDD0 needs to be installed NOT under the panel marked for storage, but under the panel marked for RAM. Yup. HDD1 is located under the storage panel, and HDD0's slot is located next to the memory modules for this computer. The casing of the notebook computer doesn't easily call this out, so this isn't intuitive.
I could not find any online references that told me this, not even the product manual, so I had to figure it out the hard way through trial and error. Hope this saves someone some headache out there!