If you have more than one Google Home device, it's easy to pair the speakers to play audio from all devices at once, and to quickly transfer your tunes from one Google Home to the next.
If you have not yet set up a Home group launch the Google Home app, tap the plus sign at the top left of the home screen and choose 'Create speaker group'. Select the speakers you wish to include (these must be on the same Wi-Fi network as your phone or tablet), click Next, then give it a name and click Save.
If you have already set up a Home group but want to add new speakers to it, launch the Home app, select the icon for the speaker you wish to add, then tap the cog wheel icon to enter the device settings. Scroll down to and select Groups, then assign it to your existing Home group and press Save.
To play audio on a single speaker you speak the usual command. But to play audio on all speakers simply say "Okay Google, pay [song name] on Home group."
Google has now introduced a new feature that lets you move music from one speaker to another, without it having to play on all devices in the Home group. The new 'Stream Transfer' feature accepts this command when Google Assistant devices are configured within certain rooms of the house - just say "Okay Google, move music to the lounge," or kitchen, or wherever.
If you haven't already told Google in which room the device lives you'll need to specify the name of the device, for example "Okay Google, move music to Bedroom speaker."
Get more out of Google Assistant: Here are 150 funny things to ask your Google Home device.