Hi Heather! A lot of people encounter this situation when designing a new course. The goal is to begin the performance-based part of training with participants who share a common skill level in the basics. In setting measurable learning objectives around base knowledge such as the architecture, consider focusing on lower-level skills. For example: recite the parts of the architecture, recall the purpose of each part of the architecture, etc. For participants who can 'do' that already, consider learning objectives around mid-level skills, such as: chart the workflow for [xyz process using the architecture], list common failures that occur [in the xyz process they charted], explain underlying causes of common failures in [doing xyz with the architecture], describe how to recover from [xyz failure]. Once the base knowledge can be demonstrated, you're ready to move on to designing the performance-based part of your course, which is what most people think of as the 'doing.' Does that help? Good luck!