Create a registration page for your fitness course or any other class you might be offering. Depending on how your courses run, you can link them out to a scheduling program, like Calendly, or add an Ecommerce button to have them pay without leaving your page. You can add a tag to your Ecommerce button that triggers a campaign message with your payment receipt and registration link. Include testimonials to show how much other's enjoyed it and offer a link for them to join your Newsletter.