When we consider the way that we learn language, we begin with a substantial vocabulary which we use and refine for 4-5 years before we actually learn to read our first words. (See my article on the Music/Language Parallel)
Following best practices, before we learn to read tonally, we should have amassed a vocabulary of tonal patterns in both major and minor tonalities. And, those should be the first words we learn to read.
Building a Tonal Vocabulary
Before you embark on this course, I strongly recommend that you complete my Tonal Audiation course, 101: Tonal Fundamentals. In this course, you will learn important tonal concepts (tonality, resting tone, harmonic function, tonic [I], dominant [V]) as well as build a vocabulary of tonic and dominant patterns in major and minor tonality.
If you are short on time, you can focus on learning the concepts and the tonal patterns in the following videos: