You got to be fit, like the sound of underwater
You have to fill out a medical questionnaire before you can start the training. It's about medical conditions you have or used to have.
You have to be fit and steady in the head to stay relaxed, never hold your breath, exhale fully, regulate your sinuses, plus there's a lot of safety precautions you need to take in diving because it could be life or death down there.
If you've taken swimming, lifesaving and other watersport training, some of this will be familiar. If you haven't you should know it's not all fun and games it's actually work. If you don't want to study or learn safety techniques or go beyond your comfort zone then maybe you will like an escorted scuba trip rather than a certification course.
These are the skills you're going to learn. The sound in this video is what it's really like to be underneath the water.