You'll first need to sign up for an account (or log into an existing account) at IFTTT . Once that's taken care of, click on "Search" at the top of the screen and enter "Google Assistant." Google Assistant is Google's answer to Siri, a voice-activated responsive search feature.
Once you get to the screen showing a range Google services, click on Google Assistant. You'll then be asked to choose which Google account you'd like to use with this service. Be sure to pick the same account you have already linked to your Google Home device.
Next, go back to the search feature and look for "Phone Call." On the resultant screen, click on "Phone Call (US Only)" (yes, this feature only works for US residents). You'll then need to go through a verification process in which you'll enter your phone number and receive a call back with a PIN number. Enter that number where prompted, and you'll be good to go with the Phone Call service.
Normally, you'd have to now link the two services together to create an applet, but that's already been taken care of you by Google, so all you need to do is visit that applet page and click "turn on." You can then leave the applet as is, or you can customize it by clicking the gear icon in the upper right corner of the black box. Do so, and you'll see three different phrases you can speak to find your phone. You can leave those as they are, or you can customize them in any way you'd like by changing the text. You can also enter in the phrase you'd like your Home device to speak back to you after it has recognized your command, as well as the message you'll hear should you choose to answer your phone when it rings.