How to set up an event through GTM?

Question

Analytics

The site has a "Call me back" button, when clicked, a pop-up is called up with a form for entering a name and phone number, as well as a "Submit" button for sending data.
In GTM, I created a class variable and specified the class of the "Submit" button in it, then I created a trigger where I specified this class, but when the "Submit" button is clicked, the event is not fixed.
Tell me what could be the problem?