I'd also like to know. I've tried doing it from the garage in car setting but I don't see an option to do it.
I've downloaded the liveries pack but still nothing. On PS4 btw.
(I'm also going to assume [MENTION=7799]AlienTaker[/MENTION] was asking about the livery creation?)
Sadly, from what I've managed to find out, custom liveries can only be implemented on PC versions at the moment.
They are done out of the game by editing a template image map file in an external image programme (Photoshop, GIMP, etc.) and then saving (after installing a free plugin to enable the use of DDS files) the result over the existing template file.
(I assume part of the reason it only works on PC is because we are able to access the file tree for the game and can manipulate the files directly.)
The template system is pretty comprehensive, although I haven't gone anywhere near anything more than the Formula A base template.
In addition to the main map that I've been playing with, there are also separate template maps for specular highlights (controls the glossyiess of the paint material) and one for fresnel levels (they control the amount and colour of reflections), as well as separate templates for chassis and roll cage paint, and another one for wheel rims. And these are repeated for every car type in the game - there's something like 550 template files in the custom livery folder.
Using all of them allows some very creative and clever people (not yours truly by any stretch of the imagination!) to create this sort of high quality work:
The application of all this effort is still very limited in practical terms though.
Because the custom template files are stored locally, only you get to see them in action on your PC. (I'm honestly not sure what online players will see when I race with a custom livery applied - a plain white car or a random livery possibly?)
That means that at the moment you could make a custom livery for your PC-using team/clan/club/forum group, personalise it for each member with a name and number, and send the files to them individually to install on their machines. But even if you were then all in the same online race you wouldn't be able to "see" your team mates' matching liveries.
Also, because of the file naming system, you can only have one custom livery per car installed and active at a time. Each time you want to change to a different custom livery, you have to resave the appropriate template files over the ones you are using.
If you want to know more, there's a fantastic tutorial that I found after my messing about yesterday here:
http://forum.projectcarsgame.com/showthread.php?21857-Vehicle-custom-liveries-How-to-FAQ