Elementary school teachers are increasingly being asked to teach computer science (CS)--a subject area with which they often have little familiarity. To address this gap, teacher professional development (PD) is a common approach for helping teachers become familiar with CS content. This paper describes a collaborative PD designed to accompany a novel seven-week instructional unit that introduces students to programming concepts by having them first play an "unplugged" board game and then create their own game levels in Scratch. We present findings from a study investigating how a group of elementary educators engaged in the PD, what they learned, and how this impacted their subsequent classroom implementations. We analyzed the educators' discussions during the seven-week PD sessions as well as their instruction during each lesson's classroom implementation. Teacher discourse during PD revealed three kinds of sense-making episodes (suggestion, reflection, and connection). We found that most suggestion episodes, as well as many connection episodes, directly influenced subsequent classroom implementations. This is indicative of the value of teacher-led conversations in helping teachers develop agency in recommending meaningful adaptations to lessons. Finally, a majority of connection episodes were grounded in the board game, suggesting that the instructional approach also supported teacher learning.