Does anyone know how to change textures on cars using wolvenkit?

So i literally started modding for the first time like 15 minutes ago, and i figured out how to change textures on clothing, but it seems more complicated on vehicles, when i look at the xbm files they look very distorted and i have no idea what i'm looking at. Right now i just wanna figure out how to add decals and stickers to the cars.

The main quest is to change the flag on the Jen Rowley to something else. Everything seems fine, i followed instructions and i think i did everything correctly, but the moment i open the game. The flag is still there and my mod is not working