How do I set the extras that spawn with modded cars?

Hey I’ve been trying to figure out how to set what extras spawn with some modded cars I have that I want to put into my server. To be more specific they are some police models by Bxbugs123. I am fairly certain there is a way to control what extras the vehicle is “required” to spawn with. However I am confused as to where to edit this and exactly how to “word” the code. I tried messing with the vehicles.meta file but when I would put it in my SP game to test if it would work it would just crash without loading. If someone could give me the basic format as to how to write the line to have certain extras spawn along with where to put it, it would be greatly appreciated. Thanks

EDIT: I HAVE ALREADY READ THROUGH THIS https://runtime.fivem.net/doc/reference.html

https://runtime.fivem.net/doc/reference.html
Search “extra”, some natives would help you I think

I’ve already read through that about 5 times and am still having issues