When I did this I used a music player app like PowerAmp. there was a setting to chose which folder to play from. Google Music is a horrible app, the service is good but the app sucks. I wish there was a 3rd party app to use with GPM service.
Would like to use Amazon music, but it won't find all my music on SD card. Poweramp does, prop something I'm missing. It finds most of it, but not all. Suggestions?
I like Samsung music too, but Bixby can't seem to use it, it tells me too upgrade Samsung music.
So I remove Samsung music and Bixby can use Google music.
I am using the Samsung music app and it automatically finds all music form my SDcard. when I add new music I never had to tell Samsung music as it finds them too.