Greetings, I am not that that skilled with with the creation kit. I want to replace the model from the Daedric Armor with the Nordic Carved Armor.

So, where can I find the models to replace them or how should I do that?

Open up both the armours and look for something like /mesh/armour/daedric and replace that with /mesh/armour/NordicCarved. Use copy paste, don't try to look for it unless you've unpacked your BSA's.