Those types of foods come with the tomatoes etc. on them already. Staff will customize them for you when they prepare it. The bars near the soda machines have ketchup, mustard, mayo, honey, etc. only.
When you order you tell them how you want it dressed as far as cheese, lettuce, tomato. But no fancy stuff like mushrooms etc. unless part of the burger you order. You order which is closest to what you want - they have about 5 different burgers with different addition on them.
Condiments are by beverage station or sometimes in bins next to the food station (great for if you are taking to go) for you to do yourself.