The tips begin at a different place in each module. The advice moves along with the stages of the course.
Most students were better at the kind of math that shows up on the MCAT in 10th grade. Don't worry. It will come back with practice. Basic trigonometry may show up on the exam occasionally, but the most important skills are the common logarithm and scientific notation. Weakness in scientific notation, especially, will cause you to miss questions, and it will also cost a lot of time.