If you decide to use the Rider Waite Smith deck, I would suggest looking at different sources online first. You will quickly see differing versions with various interpretations for the same card. This is merely a demonstration that ultimately your interpretation is up to you.
That said, study! Many people start with 'The Fool's Journey,' which is just a way to put the major arcana into a story to learn meanings. But the story, again, changes drastically. For example, the version on learntarot.com is cinsiderably different from one of the versions on the sacred texts site.
There arenalso different meanings in different decks, even based on the RWS deck.