steps

;Example with steps to activate Bluetooth on a Raspberry PI zero with Buster.

cd
sudo apt-get update
sudo apt-get upgrade
sudo apt-get dist-upgrade
sudo usermod -G bluetooth -a pi
sudo shutdown -r now

cd
sudo apt-get install bluealsa
sudo service bluealsa start

sudo bluetoothctl
#scan on
#[NEW] Device 30:C0:1B:C5:25:DD JBL GO (note: find your own device and copy MAC adress. This one is mine)
#scan off
#pair 30:C0:1B:C5:25:DD
#trust 30:C0:1B:C5:25:DD
#connect 30:C0:1B:C5:25:DD
#exit

cd
sudo nano .asoundrc
;copy next rows into this file. Use your own MAC adress.
defaults.bluealsa.interface “hci0”
defaults.bluealsa.device “30:C0:1B:C5:25:DD”
defaults.bluealsa.profile “a2dp”
defaults.bluealsa.delay 10000
;EOF

cd
wget https://www.kozco.com/tech/piano2.wav
aplay -D bluealsa piano2.wav

;Edit rc.local for connect on startup.
sudo nano /etc/rc.local
;Before last row exit 0 place next row with your own MAC adress
echo ‘connect 30:C0:1B:C5:25:DD \n quit’ | bluetoothctl