When creating or editing a subscription you'll find a section dedicated to choosing what the subscription's credits can be used for. Ie. What classes, appointment services, etc can a customer register for using this subscription.

By default, all classes you've created (and will create in the future) are included. You can remove classes by clicking the dropdown menu to the right.

Appointment services are not included by default, so if there are any that need to be included, make sure to click the dropdown and add them in.

You can choose link this subscription with another, meaning the customer will enjoy the benefits of not just this subscription but also any benefits the linked subscription contains.

Auto-enrolls allow you to choose which classes customers will be automatically enrolled into the moment they purchase this subscription.