Research shows that students have a much better chance of learning physics in physics courses that interactively engage students [1]. Relatively straightforward transformations to physics courses can have large impacts on students' learning [2]. In addition, U.S. universities are failing to recruit and adequately prepare future high school physics teachers [3] and our nation's youth are not getting adequate preparation in high school physics [4].  The Learning Assistant (LA) model addresses these problems by using undergraduate LAs to assist in the transformation of undergraduate courses and at the same time, they make up the pool from which new high school physics teachers are recruited. The LA model has demonstrated effectiveness in improving undergraduate education and in recruiting more physics majors to teaching careers [5]. In this workshop participants will be introduced to the basic components of the LA program and will learn how to use it to make practical changes in their own large-enrollment physics courses. Participants will engage with materials that are used both to train LAs and to transform our undergraduate courses.