Ah, now I get your problem! You need to install an additional program to do that - the FFMPEG encoders. I should also add here that it's not a program in the actual sense, which means it won't show in the programs menu like YouTube, but onnce it's installed, you can convert to mp3 and other formats those encoders contain.
Is it possible to add command to move for folders and files? And I have suggestion to change shortcuts ctrl+alt+arrows on alt+arrows. I think that these shortcuts were in Klango.
I have suggestions for program Files. It could be wieved creation date and date of change at folders and files. And it can be possible sort folders and files by name, by creation date or by date of change.