Assembling lasagna always confuses me. To recap, you will use the veggie/sausage mixture in the 3 layers so you mentally need to divide that into 3 portions, the sauce you will use 5 times- on the bottom, in the 3 layers and on top of the 4th layer of noodles. I mentally divide the cheese into four portions since you'll use it in the 3 layers and then the top (which is the 4th layer of noodles). Hope that helps you divide your ingredients.