Open dynamical systems allow scientists to modularly specify complicated models as the composition of primitive systems. For example, an ecologist may model a complicated ecosystem as a composition of simple interactions between species. We will implement two open dynamical systems doctrines --- composition as machines and composition as resource sharers --- using the attributed C-Set framework in Catlab. We will showcase several features of attributed C-Sets including functorial data migration and (co)limits of C-Sets in order to streamline this modular modeling framework.