Once you've adjusted your phone settings, turn to your computer. Open FaceTime on your Mac, and you should receive an automatic request, which you must accept, to allow calls from your iPhone. If the request doesn't come through, then open the FaceTime menu along the top of the screen, choose Preferences, and check the box labelled Calls From iPhone. Now, you should see incoming call notifications on the top right of your computer screen, and you can answer them on your computer by clicking Accept. To make calls from your Mac, open the app and choose someone from your contact list.