Can't add anything to WD Ultra Passport after plug-in, downloading, set-up

I plugged in my WD Ultra Passport, opened the “ReadMe” text, downloaded the Utilities & Security apps/software, but I still can’t add anything to my passport. Is there a step I’m missing?

I tried to go into Disk Utilities to “erase” and set up like all of the YouTube help videos say to do, but I can’t. It says that my passport can’t unmount or that it is “in use” even when I’m not doing anything to it.

I can’t drag and drop anything over to it. I don’t know what to do.

What macOS are you running? Is your WD NTFS formatted?