Google Home has gained multi-calendar support through Google Assistant letting users set up more than just their main calendar from their own personal google account. With this latest change anyone who wants to connect multiple Google Calendars can do so from the settings menu within the Google Home application on their smartphone, and it's a pretty simple process to configure whatever calendars you're wanting to add into the app so that you can access that information from the connected Google Home speaker that you have inside your house.
It's worth noting that if you don't have the correct update for the Home app then all you'll likely see for calendar options are the calendar associated with the main Google account and the option for a calendar associated with a family Google account. If that's what you're seeing then your Home doesn't have support for multiple calendars yet. What you should be seeing is the ability to add additional calendars and with the ability to select a Google account from which you want the Google Home speaker to pull from.
To find these options, simply go into the Home app, tap the hamburger menu, tap on more settings under the Google Assistant heading which is at the very top of the hamburger menu, then all the way at the bottom you'll find calendars. Tapping on this will take you to the calendars sub-menu where you should be finding the capability to add a new calendar, or remove one if you no longer want to have multiple calendars connected to the speaker at some point in the future. This may be the latest change that Google has added to Home's list of features which it mentioned would be available at some point, but it's certainly not the only feature that's been recently added, as a third-party company just launched a Google Home game called Drop The Puck earlier this week which asks a series of Hockey-related trivia questions to test your knowledge of the sport. Multi-calendar support also isn't going to be the last feature that gets added to the Google Home speakers either as Google and other companies will surely be coming out with new functions eventually.