Fold the sliced meat in half and place them in threes on the sub bun (ham, turkey, beef) and then repeat until you've reached the end of the bun. In other words, it uses three slices of each in a pattern (ham, turkey, beef, ham, turkey, beef, etc). When you fold the sandwich closed, this gives you those nice layers you see in the picture.
Add slices of provolone cheese, shredded lettuce, sliced onion and tomato.
Drizzle with Italian Dressing (sub sauce) and serve.
Notes
You can use any kind of bun, from Italian herb and cheese to a normal Italian.