Experiencing the grammar will enable you to know the correct grammatical unit to use. You only listen and absorb the language. Imitation does not enable you to learn a language. You learn a language by understanding the meaning of the sentences. Do your best to understand the word within the context of the sentence.
Some words take several sentences to understand because they are abstract.
As you listen to the lessons, words that are not at first meaningful will become meaningful. You know that you are learning in two ways. First, you are learning if you understand the sentences. Second, if you perform well on the tests, then you know that you are learning. The number of lessons per week is largely a decision you must make relative to the child's entire schedule of courses.