Inspect the custody route
Look at how an officer moves a suspect from the vehicle to the building and through the rooms needed for processing. Check which areas visitors can reach and where staff access should begin. The map preview is useful for establishing whether those routes cross.
Compare a city department such as Vespucci PD with the smaller-area role of Grapeseed Sheriff Station. Choose the footprint for your staffing and location, rather than assuming the building with the most rooms will work best.
Connect the station to the department
Review any required door configuration, then place the interactions used by your police job, evidence storage and custody resources. A mapped cell or desk does not supply those systems unless the package specifically includes them.
Before release, run a public visit and a complete arrest-processing scene on a test server. Verify door access with a civilian account, check the vehicle approach and inspect the location with all other nearby maps enabled.