Hello Roberto. For starters, you don't need to need to know any Spanish to book a class, but you have to make sure that your teacher is ok or able to teach level 0 students. So, it's important to always check the teacher's description, and ask any questions that you may have before booking a class.
Of course, the more you know the better as you may skip some topics, as an Italian speaker you already have an advantage when it comes to learning Romance languages, especially Spanish.
For a level 0 student, I would highly recommend getting a professional teacher, and if I may, I highly recommend Liz García, she's an amazing teacher, and although she's new to italki, she's not new to teaching Spanish:
https://www.italki.com/teacher/6099652
Now, if you want lower rates you can check for community tutors that have offer classes focused on grammar or basics, and ask them if they are ok with level 0 students.
As for myself, I'm currently developing a course to get from 0 to B2-C1, so as long as we have a common language we can communicate in, you should be fine even if you don't know a single word of Spanish. Now, the course is not even close to being complete or finished, I'm just at the very beginning of the development stage, and it's not designed to be a crash course where you will magically learn to speak in 3 weeks, but a course that will take time going through the language step by step.