Honestly? Make it the day before you want to serve it, (or at least the Bolognese) tastes better.
My recipe is:
Finely chopped onion, celery and carrot sauté for 30 minutes +
Fry off mince , add more onion, garlic and the mixture above with seasoning and oregano. Add chopped tomatoes and cook on low heat for at least 30 minutes.
Meanwhile make white sauce - I use sunflower oil, flour , milk, oregano, seasoning then strong cheese.
Assemble with layer of mince mix, layer pasta sheets, layer of white sauce and repeat. After final layer white sauce sprinkle with chopped parsley, sliced mozzarella and hard grated cheese. I make six large portions and freeze half.
Fresh pasta is nicer but you can make a very decent lasagna using the cheapest mince, bulked out with extra veg, lentils even, skip the fresh parsley and use strong cheese as you can use less skipping the mozzarella, get more portions out by adding salad, garlic bread