On Real Spanish, when you click “Sign up” or “Regístrate”, you will arrive at the initial signup form. Ignore “Login with a school” and “Login with Teachable”, unless you already have a Teachable account. Put in your details and create a password.
You will receive a message of confirmation in your email. Then, to get access to the courses, select “Login” and you’ll arrive at the login form where you just put in your email address and your password.