Make a good dough and let it rise until it has about doubled in size.
Cut the salami-slices in 4-6 pieces each and fry them lightly until the oil starts oozing out. Remove salami from the pan. Add two minced cloves of garlic and fry off the beef in the remaining fat. Sprinkle over some salt. Remove mince from pan
Fry the onions and peppers lightly so the worst of the moisture is taken out. This keeps the crust crispier later on.
Divide the dough in 4 pieces and roll each piece into a nice round. Spread half of each round with some tomato sauce, except for a border of about an inch. Divide the meats and vegetables over the tomato sauce, sprinkle with oregano and olives.
Spread most of the cheese on top. Make a paste of some water and a bit of flour and brush the rim of the dough all around. Flip over the uncovered piece of dough and seal the rim by pressing firmly together. Top with the remaining cheese
Bake the calzones in the hottest possible oven. I like to use a heated pizza-stone to get the bottom extra crispy and bake mine about 10 minutes at 250 degrees C.