If you're an Android user, all it takes to start a smart home is a Google Home app and a speaker.
Google's guide to smart home device development
See smart home devices that work with Google
The best smart home products that work with Google Home
What smart home devices work with google home?, by Prithviraj K Tagadinamani
How does Google Home work?
Everything You Need to Know About Google Home - Adorama
Google Home App Setup: a Complete Guide
How to set your home and work address on Google Home
Google Home Vs Echo: Which Smart Speaker Is Best For You?