Thank you everyone for your patience. You are stars!

Do I have to create a mods folder?
i.e for an install it is saying put the files into GTAV/Mods/x64e.rpf/levels/gta5/vehicles.rpf
But I haven't a mods folder yet?

Just noticed that! Thanks, what an idiot!!!

I take it the rest is straight forward after this?

Same thing, if this is the right one now?

This is what I get on OPENIV.

Apologies, I have done that, but it is saying there is no .exe file contained.

Thanks for the replies.

I am opening OpenIV then selecting the correct file path to where the .exe file is, but nothing inside of the files is showing, including the .exe

And yes, definitely clicking the GTA 5 files.

I use a shortcut from the desktop when starting the game normally.

When I start OpenIV it will not locate the .exe folder.

I have a Green V (Play GTAV) with a yellow and blue shield on it.

Yes that file path exists.