Motherboard and pc case wires

[Monte Cristo]

Im usually keep my pc case and it's components clean, but when it comes to reattaching those pesky little wires that connect to the motherboard from the case I get extremely frustrated, is there a simple way to connect them? And how do you know which one goes in and out? (I need contantly to take foto of it, when taking apart), thanks or fast reply.

[David (PassMark)]

You read the user's guide that comes with the motherboard.
On all recent machines the cables are labelled.