Just keep your carbs under 20 and you’re fine. Don’t purchase a meal plan, totally not necessary.
If you want to eat three meals a day, then keep it simple, for example.
Breakfast: 3-4 egg scramble with spinach cooked in butter, with 3 or 4 slices of bacon, half an avocado
Lunch: 1/4 of a pound of ground beef cooked in some olive oil, mixed with some good cheese (not the fake stuff or preshredded with potato starch as a preservative), side of brussel sprouts also cooked in olive oil
Dinner: Fatty ribeye steak cooked in butter, side of bacon wrapped asparagus drizzled with olive oil, half an avocado
Eat that for a week, I was doing something similar when I was still eating 3x day and it worked.
As far as portion sizes, just stop when you feel yourself get full.