Plug in your Chromecast and turn on the TV
Open the Google Home app on your phone or tablet
Make sure your phone or tablet is connected to the same WiFi network you want Chromecast to use
Tap the plus icon or Add
Select Set up device
Choose New device
Select your home
Follow the on-screen steps to find your Chromecast
Confirm the code shown on the TV and in the app
Choose your WiFi network
Enter the WiFi password
Wait for Chromecast to connect and update if needed
Finish the setup in the app
Test by casting from a supported app