Summarize the following:
Pull out a length of aluminum and cut it to a rectangle, about 24 in × 12 in (61 cm × 30 cm). Cut 2 more sheets of the same length and stack them on top of each other. Put your first lasagna sheet on top of the stack of foil. Use a spoon to spread a thick layer of tomato sauce, either store-bought or homemade. You can use fresh lasagna sheets or oven-ready. Pour your spinach into a bowl and mix in the ricotta cheese with a spoon, stirring until the spinach is evenly dispersed. Spoon about half of it onto your tomato sauce and spread it evenly. You’ll be using the other half of the cheese-spinach mix on the second layer of lasagna. Use your hands to spread about half of your mozzarella cheese on top of the ricotta and spinach in a thick layer. Top it with Italian seasoning, dried garlic, and onion flakes, to taste. Using dried onion flakes instead of fresh onion will help you avoid adding any extra moisture to the dish. Press a new pasta sheet on top and layer on the tomato sauce, the rest of your ricotta-spinach mix, mozzarella cheese, and spices. For a traditional lasagna look, simply press the last pasta sheet onto your second layer of toppings. For a nicer presentation, you can also cut the third pasta sheet into thin strips, about 1⁄2 inch (1.3 cm) wide, and weave them together to create a criss-cross pattern on top. You can sprinkle more herbs and cheese on top for some extra flavor.

Summary:
Cut three sheets of aluminum foil to cover your lasagna. Place a fresh lasagna sheet on the foil and spread on sauce. Mix the ricotta cheese and spinach, then spread it on the sauce. Sprinkle mozzarella cheese and spices on top. Place a new pasta sheet on top and repeat the layers. Set your last pasta sheet on top to finish.