convert multiple files?

[bdbd]

Hello, I've read that VLC has the ability to convert multiple files. I'm unable to do that at the moment. I have 45 audio files, wma format, named/numbered: 01 filename.wma, 02 filename.wma, ...
I select File -> Convert / Stream. I select all the wma files in the Finder and drop them on the Drop Media Here box, and just the first file, one single file, is chosen. I try instead dropping the folder containing the 45 wma files, the folder appears there. I pick Audio - MP3 in Choose Profile. I choose Save as File, choose destination folder and type in the-new-name.mp3. Click Save. Then I get over and over "The output file already exists." error boxes. It seems to be trying to save each individual file with the same file name for each of the 45 files, which is useless. What I really want is one single mp3 joined file -- all 45 concatenated/joined as a single mp3. Failing that, 45 mp3s numbered so that they have different names (maybe there's a way to use the original filenames but with a new extension, mp3?). Any ideas how? Thanks.

MacOS 12.6
VLC 3.0.20 Vetinari (Intel 64bit)