Hi aleksey, do you get any error messages when trying to play audio manually, ie trying to test the sample.wav using aplay?
The upboard isn’t a supported device for the audio block; you’re welcome to try but it’s going to require some experimentation & I can’t guarantee it will work. I see someone else has tried to get audio working in this balena os - upboard - audio playout issue - #18 by gzett forum thread, could you review the posts there and see if any of the suggestions help?