It is best to start with a description of the research or observations that are going to be performed in the lab. With this description, it becomes clear what you will need with respect to:
Participants (e.g. how many people are present during an observation, adults and/or children)
Equipment (e.g. cameras, computers, eye trackers, and physiological measurement systems)
Location (e.g. stationary or on-site, how many rooms)
Technical specs (e.g. how many video streams, quality of video, security of material)