Principiantes absolutos
Absolute beginners are learners which have had no or very little instruction.
There are plenty of resources available to people interested in learning a new language such as apps, music, series, films, books and podcasts, which means that the majority of students nowadays have had some previous exposure to Spanish before starting a course.
Knowing some expressions or vocabulary (even quite a decent amount or words), but having no conversational experience in real situations (other than, maybe, ordering in a bar or getting by in similar situations), may not qualify as being an advanced beginner.
Starting from the very beginning does not mean spending hours learning and practising the alphabet before actually getting down to work.
Even most false beginners, that is, learners who have studied Spanish before (in school, maybe, often for a number of years, but never acquired any real grasp of the language, and who usually pick up speed as they remember past lessons) may, in fact, benefit from starting from zero to build a solid basis.
Remember that classes are conducted monolingually in Spanish without the use of the students’ own languages, even with absolute beginners: students will start talking from minute one : )