To track the conversion rate of incoming SMS via a link using Google Analytics, you need to create a Google Analytics account and obtain your unique tracking ID. You then add the tracking code to your website's code under the `<head>` tag. To make the link to your website trackable from an SMS, you use campaign tags in the URL, which can be manually added or created using a URL builder. The campaign tags allow you to specify that your traffic is coming from an SMS versus standard web traffic. Once set up, you can test and obtain tracking data for your campaigns by navigating to real-time reports or "Acquisition" on the left nav bar, selecting "All Campaigns".