how to get all mp3 music files from an usb stick in the queue of the djay app (as songs title|artist)

The easiest way would be to use a folder on an usb stick as the source for the automix function of “djay”. But as I know, there isn’t a way to access usb devices from the djay app. So I copied all files in a subfolder of the documents folder and then wanted to copy all those mp3 tracks in the queue of the djay app. But unlike other DJ-Apps there seems no way to access the file manager of the system.
On the support pages of algoriddim I could not find any hint how I can do it.
But I cannot believe that djay (algoriddim) isn’t able to do this. Does anyone know a solution?

Thank you in advance,