Keep it simple.
Don’t worry about roux or bechamel or any of that when you’re learning. You need:
- Goop
- Cheese
- Noodles
Nothing else.
Goop consists of sauce, beef if you want beef (and for me, fuck yeah) and the spices and whatnot of your choice. Your goop should be pretty thick. If you try to make goop out of spaghetti sauce, thicken it with tomato paste, or reduce it. Then add whatever you want. Go crazy. Throw in garlic, onions, parsley, basil, spinach, anything you think would suit your taste. Do not try Aspirin or roofing nails. Keep tasting it and adding more stuff.
The cheese comes in two forms: The Gooey White Cheese and the Melty Yellow But Maybe Also White Cheese. Some people prefer their gooey cheese to be ricotta. Others go with high fat cottage cheese. The melty cheese can be most anything but stick with a pasta-friendly cheese. Mozzarella is a safe bet for your first try.
Then get noodles. As has been pointed out, boiling the noodles is a waste of time. The moisture in the lasagna will cook them. I think ready-bake works better but whatever.
Get a big fucking pan. Put down a layer of goop, then scatter some of your Gooey White Cheese, then a layer of noodles, then shredded yellow cheese. Repeat. You’re probably near the top of the pan. If you aren’t, do another layer. Then on top put a thin layer of sauce on the choose, then more cheese. By the way, this process is way, way more fun if you’re drinking. (One advantage to having ground beef in your recipe is that it makes the process longer, enabling you to drink more.)
Put that son of a bitch in the oven at 375 for like 45 minutes, at least. Maybe an hour. Tent it under foil except for the last ten minutes. Remove and let it sit, torturing your guests with its incredibly delicious aroma, for at least twenty minutes. Then chop that bad boy up and serve.
Hint; do it right and it’ll taste WAY better the following day when you reheat it in the microwave and eat like a pound of it while watching TV.
I’d give you my specific recipe, which varies from my beginner’s guide, but it’s the most important secret on earth. Every single person who has ever eaten my lasagna has pronounced it the best they have ever eaten and in some cases say it’s the best food they’ve ever eaten.