Audio File Processor is not detecting mp3 files in my folder

[CB490]

I am trying to add an audio sample into my song, but when I try to import the audio file via AudioFileProcessor, the mp3 file does not show up. How do I fix this?

[Gps]

You need to convert the mp3 to something LMMS can read.

Audacity can do this.

[musikbear]

I try to import the audio file via AudioFileProcessor, the mp3 file does not show up.

That is unfortunately correct.
LMMS does not support import of mp3, because of earlier licences costs.
The formats supported are:
* wave
* ogg
* ds
* flac

Besides that, since you are new in Forum
Welcome CB490 !
Here are all important links:
viewtopic.php?f=1&t=4740
-A few rules and useful forum instructions