Tagging multiple folders

Hello All -
I'm new to Mp3Tag and the group and think that I have found my way around the basics but have quite a specific need. I have nearly 4,000 folders on my hard drive, each of which is an album. They are arranged in folders alphabetically by artist, A has AC/DC to Art of Noise as sub-folders, B has Derek B to Byrds, C has Cactus World News to Curved Air etc all the way through to Z. The albums I ripped from CD using EAC aren't a problem and have a tag but I also have many vinyl albums and cassettes that I ripped using Audacity which don't have tags.
Can I get Mp3Tag to automatically add tags to those folders that don't have one already? I appreciate that I can do this by going through each album/folder myself but that would take ages.
Hope I've given enough info. Thanks for any help.

What do you mean "don't have tags"? if there is no information in the files or the folder names then it is not possible for MP3tag to "guess" which track a file might represent.

So could you please explain with a typical example which data is there and which is not?

For those that do not have tags you can probably get some tags from the folder-names and/or the filenames, i.e. Artist, Album and Title.

With this information the best way is to use the Websources of MP3Tag album per album to get track informations.

Hi - thanks for your help.
So, the ripped first CD of the triple set Bruce Springsteen Live 1975 - 1985 is in a folder titled "24. Bruce Springsteen - Live 1975-1985 CD1". Each track from that CD is then in that folder: "01. Thunder Road.flac; 02. Adam raised a Cain.flac; 03. Spirit in the night.flac" etc. There is also a an M3U file in the same folder, "Bruce Springsteen & The E Street Band - Live 1975 - 85 (Disc-1)". I assume that this was generated when I ripped the CD.
(It may be worth pointing out that each album file name is prefixed by a number that I have given it so the album appears in alphabetical order by artist - Bruce Springsteen appears after Victoria Spivey rather than at the top of the list as would happen if it sorted on "Bruce".)
Pete Seeger - Gazette which was ripped from vinyl is by contrast is in folder "08b. Pete Seeger - Gazette" (Same numbering format) with each track numbered as above but there is no M3U file.
Now, I accept that part of my problem is that I do not fully understand how the system works but when I play music on an Ipod it often doesn't "know" which track it's playing (All the tracks are also ripped to mp3 for the Ipod) whereas my Sonos system seems able to read the track titles directly from the PC NAS drive even when there's no M3U file. Frankly I'm confused so any help is very gratefully recieved.

You could fill the tags e.g. with the function Convert>Filename-Tag
%dummy%. %albumartist% - %album% CD%discnumber%\%track%. %title%