How to retain source files

[Chamomile]

Hi, I'm a tech noob who is new to this software.
Sorry if my explanation is incomprehensible...
Any help will be greatly appreciated!

Problem;
I can't find the source files of the music I imported from Walkman after I edited them on MusicBee, and it causes all the edited music files to vanish

Background information;
I record music on Walkman using a recording cable, and then import them to MusicBee so that I can edit the titles, artists, and so on.
I import the files from Walkman to MusicBee using drag-and-drop, moving files from the "NWWM_REC" file in Walkman to "All Artists" category in MusicBee.
After editing, I right-click on the edited file on MusicBee and choose "Send to" > "Device Walkman(E:)."
Usually it won't import the files to Walkman somehow, so I always use drag-and-drop afterwards (if you could give me a solution to this phenomenon, that would be beyond helpful).
At first it worked, but after a couple of times I realized that MusicBee began to say something along the lines of "the source file is missing" when I double-clicked on a song and I can't play that song on MusicBee.
After I disconnected Walkman from MusicBee, I also realized that the corresponding files were missing from Walkman.

I used to rely on Music Center for PC, but stopped using them because my files often got missing out of the blue.
Now I changed my music manager to MusicBee, but it seems I can't get a hang of this software on my own.

How can I import files from Walkman, edit them on MusicBee, and then import the edited files back to Walkman without missing files?

[vincent kars]

Looks like you want to use Musicbee to tag the files on the walkman only.
A simple one is
create a new library "walkman"
point it to Walkman(E:)
Set its monitored folder to Walkman(E:)

Connect the Walkman and select this library in Musicbee.
Now you are simply editing straight on the walkman.

[Chamomile]

Thank you so much, Vincent!
I followed your guidance and think it's working!