Change audio track while playing video - Real Vision 4k

[BigZ12]

Hi,
I sold my Dune Real Vision 4k, and the new owner cannot find how to change audio track while watching a movie.
It somehow chooses a stereo track, or often commentary track instead of the surround/atmos track...
I don't remember how to do this, can you help?
Best BigZ

[isolar801]

You just press the lined button above the wheel to select audio tracks....but something is wrong with his files if secondary tracks play instead of the default main track.
He needs to check them in mkvmerge and fix them if need be.

[BigZ12]

You just press the lined button above the wheel to select audio tracks....but something is wrong with his files if secondary tracks play instead of the default main track.
He needs to check them in mkvmerge and fix them if need be.

Thanks! (it was a Flac file )