After completing an assessment, ALEKS will recommend one of five different Prep and Learning Modules to provide you with the opportunity to improve your skills. The modules are: Prep for Beginning Algebra, Prep for Intermediate Algebra, Prep for College Algebra, Prep for Pre-Calculus, and Prep for Calculus. Topics for each of these are available on the ALEKS web site at https://www.aleks.com/highered/math/prep/.
You only need to make use of a Prep and Learning Module if you wish to improve your placement score. However, even if you are happy with your score, making use of the modules will help you do better in your course.