This project note describes challenges and procedures undertaken in annotating an audiovisual dataset capturing a multimodal situated collaborative construction task. In the task, all participants begin with different partial information, and must collaborate using speech, gesture, and action to arrive a solution that satisfies all individual pieces of private information. This rich data poses a number of annotation challenges, from small objects in a close space, to the implicit and multimodal fashion in which participants express agreement, disagreement, and beliefs. We discuss the data collection procedure, annotation schemas and tools, and future use cases.