Transferring files from external hard drive to My Cloud PR4100

I have a WD 6tb My Book external hard drive that has a lot of movies on it. I’m trying to move those movies onto a My Cloud PR4100 but it’s an unsupported file system. How would I go about getting those movies onto the NAS drive so I can have a media server setup for watching movies in my home?

If the My Book external desktop USB hard drive is not recognized by the PR4100 when one connects it to the USB port of the PR4100, then one will likely have to connect the My Book to a computer’s USB port and copy the files, using Windows File Explorer or Mac Finder, from the computer to the PR4100. A few relevant WD Knowledge Base Articles (more can be found/searched for at the Knowledge Base link at the top of the page):

External USB Drive Will Not Mount, Not Seen or Detected by a My Cloud

External USB Drive File Systems Supported on a My Cloud

My Book not detected by NAS, Router, DVR or My Cloud