How to propagate the MacOS UID/GID

[pkcyll]

Hello, this is my first time posting.

I am using the Asustor to backup, via TimeMachine my iMac, and to free space on my hard drive.

The directories I moved from my iMac to the Asustor are the contents of Pictures, Movies, and Music.

However, when looking at the owner of these, stored under my username, when doing a Get Info, I have two (unknown) [the owner and Group] and everyone in the Name column and the Privilege are set to Read and Write for those three Names. When trying to change the first (unknown) which is the primary owner to my MacOS userid (ought to be "Philip"),I get a dialog panel telling me that "The name you entered isn't valid. Please try again." Trying to change the privileges away from "Read & Write" from the second (unknown) [the Group id, ought to be "staff"] and "everyone" to "Read Only" gets me a "beep" and the action is not done.

How do I fix this? Thanks