Underneath Settings → Services & Classes, you'll see the main Services & Classes screen where you can click into and manage all of your existing services and classes or add a new service/class for clients to book with you:
On this screen you'll find several features including:
After making any changes to your services or classes (whether that's just editing a service's duration or adding an entirely new class), it is a good rule of thumb to quickly preview your client facing scheduler to make sure your service availability or class schedule looks accurate. To do so from the Services & Classes screen, simply click the "Preview Scheduler" button in the top right corner:
This will launch your mini website on a new tab where you can click through your scheduler and check out your "Services/Classes" and/or "Time" panel to make sure that your appointment offerings and available time slots look correct for your different services and classes.