Name of adapter/wire/cable used to string together multiple NAS HDD?

What is the name of the adapter/cable used to connect multiple NAS HDD?

Do i need server PSU to power them?

Do i need to have a NAS server case? Do you know a cheap one?

What is a NAS HDD for you? Drives are usually equipped with a SATA or SAS connector.

No offense, but do you know what a NAS (network attached storage device) is? It is a device, like Synology or Drobo or a Windows or Linux server that takes SAS or SATA drives and shares them over the ethernet to the network then if allowed, to the internet.

If you choose to build a NAS, get a Dell R7xx server with multiple drive bays and use that as the NAS. It will have everything you need (maybe not the boot drive or OS or RAM) but it will have everything you need to link multiple drives and share them over the network (assuming you even know what that is).