App send name music to bluetooth

Hi guys.
I did a search here on the topics and did not find what I need.
I have a multimedia player that automatically connects to my device via bluetooth.
When my app starts up, it already receives the list of existing Mac addresses.What I need is that my device sends my label information to the media player. For example: in my app an mp3 is playing and my label has been set to “demo.mp3”. I need the label name (“demo.mp3”) to appear on the media player screen automatically, but I am not able to do it.
And I also want the media player to send play and pause commands to my app. Can someone help me please ?