Although most people know a few things on In-N-Out's secret menu, not everyone knows all of what In-N-Out has to offer. It offers all sorts of stuff besides the classic burgers and fries, like specialty shakes and Animal Style burgers. Also, the steps aren't steps, they're each a menu item or custom ingredient/style.
Step 1: The Flying Dutchman
This is seriously just two pieces of meat with cheese in the middle. Or, if you want to go hardcore, you can get it animal style, where they cover it in Spread, pickles, and grilled onions.
Step 2: The 4x4
4 Meats, and 4 Cheeses. The very hungry man's Double-Double. Variations include the Triple-Triple, 2x4 (2 Meat, 4 Cheese), and 4x2 (4 Meat, 2 Cheese).
Step 3: Animal Fries
A regular side of fries, covered in Spread, cheese, and grilled onions. Or, you can go for nachos and get just cheese.
Step 4: Protein Style
Instead of the bun, why not go healthy and have lettuce instead? (Cheese not included.)
Step 5: The Neopolitan
A majestical (-TM-)RossTheGreat) mix of vanilla, chocolate, and strawberry shakes, all in the same cup.
Step 6: Root Beer Float
ICE CREAM AND ROOT BEER TOGETHER. AT IN-N-OUT.
Step 7: Grilled Cheese
Just cheese on bread. Good for small children.
Step 8: Veggie Burger
A bun full of lettuce, tomatoes, onions, and pickles, with grilled onions on request. No meat.
Step 9: Extra Ingredients
Sone if the extra stuff you can have added to your burger are fries (in your burger), chopped grilled onions, a whole slice of grilled onion, chopped chilis, and classic mustard and ketchup.
Step 10: Other Options
Other stuff you can do to is to have cold cheese slices, no toast or extra toast on the bun, and you can get your meat medium rare. You can get a burger mustard grilled, which is where it's grilled in mustard. Also, you can get a burger Animal Style, with extra Spread, pickles, and grilled onions, and it comes mustard grilled.