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. We recommend no less than three times a week for a half-hour. We recommend that each lesson be taken at least twice.
Some parents have their children take each lesson three times.
We also recommend that lessons should be reviewed. It is helpful when completing a later lesson, for example lesson 7, to go back at least four lessons, for example lesson 3, when reviewing a lesson. Later lessons often increase understanding of early lessons. Do not imitate the sentences. You learn by understanding, not be repeating.