[HELP] Vehicle Adding that aren't replacing default vehicles

As said in this thread

Hello, I would like to know how I would go about adding more police vehicles, I have a couple of vehicles I would like to add although most of the slots are already full, So I want to add additional vehicles, Example: police5, police6 or like sheriff3, sheriff4 etc etc, I’m believe you need to use data / meta files for that? I’m not exactly sure.

They are requesting on how to add vehicles that aren’t replacing current vehicles and give them they’re own names as well. As listed in the thread people link guides that only show you how to replace vehicles that are current in-game, I don’t want that, I need help on being able to add in cars that go by they’re own names such as “statecvpi” etc