The enrolment of software engineering students has increased rapidly in the past few years following industry demand. At the same time, model-driven engineering (MDE) has become relevant to other domains like embedded systems and machine learning, in addition to traditional software engineering. It is therefore important to teach students MDE skills in an effective manner to prepare them for future careers in academia and industry. The use of interactive online tools can help instructors deliver course material to more students in a more efficient manner, allowing them to offload repetitive or tedious tasks to these systems so they can focus on individual and group teaching activities that cannot be easily automated. Interactive online tools can provide students with a more engaging learning experience than static resources like books or written exercises. While there exist multiple modeling tools that allow students to build a domain model, none of them offer an interactive learning experience. In this paper, we explore the interactions between a student modeler and a modeling assistant application that allows students to build domain models with the help of an interactive system. We present the concepts required for the interactions using a metamodel and illustrate with three examples. We explain how to form a corpus of learning material that supports the assistant interactions. We also use the metamodel to show how this system will be able to point out mistakes, offer hints, and point the student to resources from the corpus so they can learn more about a given concept.