mp3 files on Nexus 4

[Zsolt Balasy]

Hi, Im stuck. Google Play Music only plays those mp3 files that were initially(?) on my Nexus 4. The ones I added later, I cant play with that app and have no idea how to add them to the files to be played. So I downloaded a File Manager and can open those new mp3 files with it, but then I cannot multitask. Anything I press makes the podcast stop. Tx for the help.

 

[Zsolt Balasy]

Maybe I wasnt clear enough. I can open my mp3 podcast files on my Nexus 4 only through some kind of file browser, like Total Commander. But they only open them such way, that they dont play in the background (like Music Playr does) so if I click on anything else, then the mediaplaying disappears and I have to start it again, and find where I was at. How can I add these podcasts to the music library?