Goto Alexa App home icon that are present at the bottom right side of corner.

In device mmenu need to select the Echo and make the pair

Then need to open or tap  on the Bluetooth device according to model number.

Done the Pairing the Bluetooth device with according to model number.

Now select the Bluetooth Speaker

You will able to hear the Alexa or listen the music by Echo Dot. (Read Also Echo Dot Offline)

If still the Problem with How to Connect Alexa to Bluetooth then contact the Alexa Echo expert today.