We describe an innovative preorientation curriculum (POC) for a Master of Biostatistics (MB) program. The goal of the POC is to fill critical skills gaps for students entering the MB program from heterogeneous backgrounds so they are prepared to engage in the program's rigorous, fast-paced training upon arrival. To achieve this goal, we introduce a structured approach to thinking that forms the foundation of a sound mental map of Biostatistics, which will assist students in their subsequent efforts to master the discipline. Based on constructivist principles, the POC covers mathematical and statistical theory, data analysis methods, programming, and statistical practice through a sequence of instruction that encourages reflection, extension, and connection between topics. The POC is modular, self-paced, and offered online via a cloud-hosted interactive learning management system (LMS). Students are required to complete the curriculum prior to the MB program orientation. We describe the rationale, design, features, and initial evaluation of the POC. Finally, to help programs interested in designing similar curricula, we provide a detailed instruction sequence description of one topic.