Would anyone be able to help me out with how to get the vehicles/other features I downloaded work in the game?

I can help you out man, it's very easy to be honest!

 

You need a car replacement, OpenIV and that's it usually, what part you don't get?

@newbie I don't know how to put the files into the correct place to get them to work properly

1 hour ago, capsfan147 said:

@newbie I don't know how to put the files into the correct place to get them to work properly

Here's link to tutorial videos: https://www.youtube.com/results?search_query=how+to+install+els+police+cars+in+gta+5

Make sure you have ELS installed and to download ELS vehicles. If not using ELS, try watching these videos: https://www.youtube.com/results?search_query=how+to+install+police+cars+in+gta+5

Download page if you want ELS: 

 

Personally my open iv is set up in a weird way. If you need any help contact me.

45 minutes ago, alext17 said:

Car files go to latest patchday in OpenIV. (Update/x64/dlcpacks/patchday14ng/dlc.rpf/x64/levels/gta5/vehicles.rpf).

Thanks so much!