Croquet collaborative learning environments are computer-mediated three-dimensional social environments where users create and modify the shared virtual world simulation. Users build and modify Croquet collaborative spaces by creating new spaces, linking spaces together, and populating spaces with objects. The spaces and objects that users control can have behaviors and other attributes which users may modify. This flexibility presents unique challenges in designing a user interface that is functional for a user community with a wide range of experience and expertise. In this paper, we examine how the user interface can support user control of things and places in Croquet-based collaborative learning spaces, and propose a set of initial user interface conventions so that we can start the trial and error process of developing the optimal user interface for Croquet-based collaborative spaces that support learning and instruction.