How to back up multiple users on multiple computers?

I believe this is in the right place, but if I’ve chosen the wrong forum I apologize. I’ve been asked to back up several computers in our lab using an 8TB My Book WD External Drive. Each computer has between 5 and 10 user accounts on it, and I’m not really sure how to go about backing up all data. I thought I knew what I was doing and managed to back up the computers, but after checking the drive, it appears that it only backed up my specific user. Do I need to install the external drive separately for each user account on every computer?

I did try searching the forums first and found the following two posts, but I’m not using the My Book Live, and I want to make sure that there isn’t another simpler option to performing separate backups for every user separately.
Backup of multiple user’s data
MY BOOK LIVE - Backup multiple computers


What backup software are you using?

The WD Backup that was installed with the drive.


It is possible to backup all the user on the same computer.

You just have to create a “File backup” and select all the user’s folders.

That was what I initially tried. The result was the following screenshot. I had chosen to include all files, but the .dat files for the other users failed to back up. Does this mean that I will need to log into each user separately and back up their information separately?