How do I make Alexa play music on all my Echo devices?

Make sure that All the Echo devices are connected to the same Local Network and the Alexa app should be up to date.

1. Open the Alexa app
2. Select Devices on the bottom-left corner
3. Select the ‘+’ icon on the upper-left
4. Select Set Up Multi-Room Music
5. Setup screen appears, tap on Continue
6. You can now set a name for the Group but we’ll just use Everywhere as an example (You can also select the common names listed below like Everywhere, Kitchen, Living Room, etc.). Just click next after picking one
7. Select all the Echo devices that you want to add on your Everywhere Group (Your customized group name), then just hit Save
8. After ‘Connecting your Echos’ screen, the set-up is finished

All that is left to do now is to say “Alexa, play ‘music/artist’ on ‘Everywhere’ Group’” and check if all the devices added to the group are playing the requested music. Cheers