LyricsLover > I really only need to rename the files to PLEX format. I've tried that on another test file and PLEX now picks it up.
I'd like to know how To create a Tag Panel field, but it's not the priority I thought I needed.
Oh, and I figured out the Alt-T action.
MotleyG > Thanks for this add'l input. It clears up some points for me. Unfortunately, the only file information given is the title, so I'm going to convert that to PLEX standards and be content with that for now.
Doug_Mackie > Thanks for your comments. I have come to your suggested solution and try learning about tags later... hopefully with the aid of my earlier contributors "ohrenkino", "LyricsLover", and "poster".
Two ways:
a) Use a specialized file rename program and create the structure as PLEX need it
or
b) Use Mp3tag
In Mp3tag you can use Convert Filename -> Tag and fill the existing parts from your filename to your tags with this format string:
%ARTIST% - [%SEASON%x%EPISODE%] - %TITLE%

Then you mark all your episodes and fill the additional YEAR with
2004
Alt+T should look like this for Episode 2:

Then you can create the PLEX structure with the Convert Tag -> Filename and this format string:
%ARTIST% (%YEAR%)\Season 0%SEASON%\%ARTIST% (%YEAR%) - s0%SEASON%e%EPISODE% - %TITLE%
The above format string creates the PLEX structure with the existing values in your tags.
Since the season has no leading zero, we can just add a 0 for eight seasons like above in the format string. This would not work for shows with more then 9 seasons. Then you would have to adjust the content of the season tag first.
For the record:
The tags SEASON and EPISODE are custom (not official) tags. Since PLEX seems to use a folder structure, you can use whatever tag names you like. For MP4 files there are official tag names like TVEPISODE, TVSEASON, TVSHOW as you can see in @MotleyG's screenshot.