The first unit hustles to the scene and confirms that there was, in fact, a crime and checks for prosecution. The unit then confirms or updates any information for re-broadcast to everyone else responding. This helps prevent driving past the suspect because of receiving the wrong description. Simultaneously, the same unit starts controlling the crime scene with an emphasis on securing the last known point the suspect entered and or existed. This is a must if you plan to use K-9s for establishing a track later.
With that accomplished, the second unit is free to establish a command post and start setting up a perimeter. They have also volunteered by default to be the incident scribes. They direct responding units where to deploy and document it until the supervisor gets on scene and takes over full command. Afterwards, they continue documenting positions, decisions, and instructions to avoid any duplication of effort. Obviously, this frees up the supervisor to accomplish other necessary command-level tasks.
Another basic element to a structured response is incorporating a simple numbering system to identify the sides of a building for responding units. Whatever you deem to be the front of the building, label it as side one. Going in a counterclockwise direction, give the remaining three sides numbers two through four. Calling out, "I have side three," gives an exact picture for everyone to see and makes it easier for a supervisor to track unit locations.
With this system you can also easily call out a specific corner because it is just a matter of combining two sides. The phrase, "I have corner three-four," immediately lets everyone know that officer is in the back right-hand corner of the building.
If you have an area with many buildings, just identify the building with a number and break it down the same way. You coul call out your location as, "I have side one, building one." In a larger perimeter you can still identify your location by calling out the street, nearest intersection, or landmark. If you have an inner and outer perimeter, you can use a combination of both.