Adding routines to Amazon's Alexa meant that it was just a matter of time before it came to Google, as it did earlier this year. Google will not let go of its assistant feature ̵1; the digital voice-controlled interface that runs its line of Google Home Devices and lets you interact with your Android smartphone with voice-get far after Alexa if it can help.
What is a routine? The simple answer is that you're creating Google's home to hear a single command, but it has to do several actions. You can say "Hello Google, I'm on my way out", which will trigger Google Home to start playing music to keep your dog company and turning off all the lights. Or say "Ok Google, I'm going home" and Google Assistant can write your husband to say you're on your way and restore your smart thermostat so that the temp is right when you arrive.
It can be complicated, but it's easy to set up a routine. Like this.