Since you indicated that you are trying to sign up your child for a class, you need to find the specific site your organization set up for registration, something like myschool.schooltwist.org. You don’t need to create an account in order to register.
This form is only for people that want their own registration system for classes that they are offering.
Next Steps: Look back at your original link and click it again, or look closely at the url and try retyping it.
If needed, contact us via email at firstname.lastname@example.org.