The numbers on the map correspond to the following:
1) Garage This is where the gravtrucks dock to unload their missiles for finishing, and load finished missiles to be transported to the docking bay.
2) Assembly lines The concussion missiles are completed on these lines.
3) Open area The Z-95s stop here on their way offplanet. Here, their weapons are finally attached and charged up, and they are loaded with concussion missiles. This prevents slaves from getting their hands on weapon components.