Here are the steps to configure Google Assistant with IFTTT. You will need to create two applets, one to turn on the lights and the other to turn off the lights.
Click "This" to create the first half of the applet.
Search for and select "Google Assistant". Don't be tempted to select Adafruit yet! We will be selecting that in the second half of the applet.
Click on the "Say a simple phrase" trigger. The Google Assistant trigger here is more customizable than the equivalent Amazon trigger. Here you can enter up to three phrases to run the action, and you can also tell Google Assistant what to say in response. In this example, three phrases are entered: "turn on the lights", "turn the lights on" and "turn on the living room lights". For a response, we used "OK, turning on the living room lights"
Click "That" to create the second half of the applet. Notice the Google Assistant icon in the "If" part of the applet.
Here is where we connect our applet to Adafruit IO. Select the "Adafruit" icon from the list of action services, and then select the action, "Send data to Adafruit IO".
Pick the feed we created earlier on Adafruit IO, "PyPortal Switch". For the data to save, enter "ON" if this applet turns on the appliance, or "OFF" if this applet turns off the appliance.
Review the applet to confirm and click the "Finish" button to complete. You may want to disable notifications when the applet runs to avoid getting notified every time you turn the appliance on or off when using Google Assistant.
You can now test your applet by speaking the phrase from the previous step. Don't forget you need to create two applets in order to turn the appliance on and off.