But, should you be absolutely insane while also having never made lasagne (something which I am guessing occurs at the same time a lot) I can speak to you as though you are 5 years old and teach you to waste your time like an expert.
1 lb. ground Italian sausage 12 oz. tomato paste
1/2 c. minced onion 13 oz. canned tomato sauce
2 cloves of garlic, crushed 28 oz. crushed tomatoes
1/2 c. water 12 lasagne noodles
16 oz. ricotta cheese 1 egg
3/4 lb. sliced mozzarella cheese 2 tbsp. sugar
3/4 c. grated parmesan 1 tbsp. & 1/2 tbsp. salt
1-1/2 tsp. dried basil 1-1/2 tsp. dried oregano
1/2 tbsp. pepper 1/2 tsp. paprika
You're going to want to start this several hours before you expect to eat it, because the sauce needs to simmer for 1-1/2 hours before you can even start assembling the damned thing and the baking time is about an hour for the lasagne itself.
In a large pot (or a Dutch oven, if you have one, fancy pants) cook sausage, onion and garlic until well browned - you may need to siphon off some of the oil to get it to brown properly. Stir in water, everything involving tomatoes, and all of the seasonings (including the tbsp. of salt). Simmer, covered for 1-1/2 hours. stirring occasionally.
Once the sauce is nearly done, bring a large pot of salted water to a boil. Cook noodles for 8 minutes. Rinse with cold water. Combine ricotta cheese with the egg and 1/2 tsp. of salt.
Assembly! Finally! But yeah, don't preheat that oven (to 375 degrees) until you're about halfway through putting this thing together.
Get you a baking dish. Spread about a cup of the tomato sauce on the bottom.
If you're particularly anal retentive about cohesiveness and just have ridiculous amounts of time to kill, feel free to alternate your layers with the noodles going the other way. It'll just mean that you have to sorta piece the damned thing together (this is only recommended for someone who's just been discharged from a mental institution, and finds themselves in need of bland activity) or make extra noodles and cut off the excess and either throw it at hobos or put it under your family's pillows. Be creative about it.
Cover your lasagne with aluminum foil which has been hit with some cooking spray or boy will you be pissed off later. Bake for 25 minutes, remove foil and bake for an additional 25 minutes. Remove from the oven. This step is important, because you can't get the food in your mouth unless you get the food closer to your face. Allow it to cool for 15 minutes before you slice into it, unless you want lasagne soup that burns you so badly, your screeching causes the neighbors call the authorities.
Do I need to remind you to turn your oven off? Turn your oven off.
This is how it should look: