Just bear in mind that Wikipedia is a user-updated reference, so the information is only as good as the users that update it.
My suggestion is to build a desktop computer first so you know what you're dealing with. It will give you some understanding of where things plug in and such, loading Windoze, installing drivers, troubleshooting, etc.
Those are skills you're going to need when you start building the PC for your ride.
Going into a carPC project knowing nothing about computers is going to infuriate you to no end. You're going to build it, find something that doesn't work, post a question on these forums, get flamed repeatedly, search and find the answer, apply the solution, and then repeat.