How to track where the students who signed up for my course came from?

To start tracking, attach a UTM tag to your link. Such a label will help to separate people who came, for example, from your social network and those who came from your site. To generate UTM tags, you can use any generation service, for example, https://tilda.cc/ru/utm/. The tags will be displayed in the "Clicks on links to the course" report.