Correctly add addon vehicles to server?

Alright so we are wanting to add a few vehicles to our server and was wondering how to do this and what folders i would need to edit in the server files because i assume i need to edit some client files and so on so that it will stream correctly? i could be wrong but can anyone send me a link to a thread or explain how to add them?

Hi I see that what you are looking for or having trouble with has more here, found some more who have asked for the same so you could find some help in this, if it helps then there is a link here that shows how.

This was over a year ago i have already figured all that out

how? please tell me @Tanoshi