How to know what to name your custom textures

Hey guys pretty new to modding, but I've recently been messing around with asset studio and valheim textures. I can export them no worries, edit them etc, but how do I know what I should be naming them in my custom textures folder? I downloaded one guys reskin of copper armor and I retextured that (because he had the right name for the files) but everything else doesn't seem to work.