The easiest way is not to use Bluetooth but Wi-Fi nowadays, although it is not explained anywhere.
Connect to the same Wi-Fi network your Mac is connected to.
First one needs to download the AirServer Mac app which is not free. It is the only app or option that has worked for me though. Install and open it, open preferences and click the Google Cast option.
Second: on android, use the Samsung Music app, for instance, as it plays a tune find and hit the "play" icon that's within two arrows (Smart View), it looks like a repeat button but it's not, cast to your Mac. It works straight ahead but no other program does that, and the Bluetooth streaming option doesn't work on my own Android.
Although I haven't tried it yet, you can also try AirDroid Cast, that you need to to install on Android and on the Mac separately.