The question you ask is too involved for a proper answer. You need to go to a car parts store, and get a repair manual for your car. They cost about $16.00 Or, go to a Public Library.
The images in these instructions show the replacement of the heater core in a 1998 A6q Avant. The entire C4 lineup should be the same. Be sure to have a digital camera handy to document disassembly.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.