I realized I will need to have the lineart and shadow layer over the markings I making, but I'm not so sure how to do that, does anyone have knowledge on this thats willing to give me a simple breakdown? D:
Look up how to make a clipping layer or mask in your art program. If you turn the shadow and lineart layer into clipping layers with the marking art below them, they will show up where the markings are but no where else on the canvas.