That listing shows empty drive bays or drive cages. They’re missing?
I’ll just point you to the documents for the latest Scale release, hardware section and the ZFS Primer. I think most of the needed info will be there. You are on the right track by trying to get server grade gear. Post back questions after you look these links over. There is also a hardware guide on the old forums. A little dated but still very relevant. I’ll try to post that link too