Undergraduate students tend to struggle with probability in their introductory statistics course. Probability problem solving requires several steps. First, students must make sense of the probability scenario, then determine the appropriate probability rules, and finally, execute the procedures to solve the problem. With no previous exposure to probability, this presents too great a cognitive load for many students. Using worked-out problems then transitioning to partially worked-out problems in an introductory statistics course at a large university helped students succeed at solving probability problems. The worked-out problems included writing prompts to encourage self-explanation of students' thinking through studying the worked-out examples. This paper explains the use of these instructional principles and their implementation in an introductory statistics course for non-STEM majors, resulting in higher student achievement and understanding.