Thankfully I've got a drawing tablet. Are you suggesting that I would need to put the hand-drawn picture on top of everything else, and lower the opacity? Or should I set it at a 100%?
And, yeah, I noticed I missed a few elements that were on the books... I planned to put some smoke coming from some house's rooftops as well, but I forgot to do it, and now the only version I have of the picture is the rendered one. Little mistakes like these; I will have to remember them in future maps.
Thank you both, have some rep for helping me!