[This paper is part of the Focused Collection on Curriculum Development: Theory into Design.] The communities of practice framework has become an essential framework for understanding identity development both in physics education research (PER) and in science, technology, engineering, and mathematics, more broadly. However, the use of communities of practice as a learning theory that informs curriculum design is significantly less prevalent within the PER community. One possible reason for this is that communities of practice as a theory originated in professional environments and it subsequently moved towards a framework that is centered around informing management practices. Some significant interpretations and negotiations need to be completed in order to apply and to design for communities of practice in the classroom environment. In this paper, we outline an introductory physics course called Projects and Practices in Physics (P-Cubed) that was designed using the communities of practice as a guiding framework. We present the curriculum decisions that focus specifically on the adaption process from professional practice to the classroom context along with the theoretical underpinnings of the curriculum design decisions that went into the development of the P-Cubed classroom.