Just like an airplane license, you need to have experience before you get your license. A sailing license is required for the Mediterranean. In the Caribbean only an acceptable resume is required to charter a boat - but the resume must be strong. This means you have relevant size boat experience as skipper of the boat as required by the yacht charter companies and the insurance companies.
The NauticEd SLC license requires 50 days of sailing experience, 25 of which as master of the vessel and 25 of which on a vessel greater than 28 ft.
When wanting to go chartering for the first time we recommend hiring a captain. The captain is there to ensure you have a good time. each you what you would like, give you the helm as much as you like, and generally take the initial stress off you and make your crew feel comfortable. Taking a captain the first time is the prudent thing to do.
What we recommend is to start with the Bareboat Charter Master bundle of courses in your curriculum. The first course out of the bundle to start with should be Skipper. This will give you a good start to the theory knowledge you need to start learning. Next, it is best to get with a school to get a good start to the basic practical skills. Then you should somehow gain access to a boat either through a friend or through a local yacht club. Continue to gain experience and all the while continue to pass the online courses for theory knowledge.
You can choose to start with a big boat (26 ft or greater) or small boat (25 ft or less). It is your choice. If you start with a small boat, do the Skipper Small Keelboat course. If you want to start straight out on big boats, that works too. In that case, start with the Skipper course which is focused on bigger sailboats 26 ft and above.