Template for a school

Is there a template that allows visitors to sign up for classes? 

That's unlikely to be specific to a template, but can you be a little more specific? For example, do you want people to be able to book and pay for time slots? 

With Squarespace Scheduling, clients can book appointments or classes using the Appointment Scheduling Block or through a separate scheduling page. Scheduling only displays the times you're available and encourages clients to book appointments on their own while capturing all the information you need.