It usually involves the same routine. The hostess leads you to your table, pulls out your chair before you sit down, you fold you napkin on your lap and look at the large menu to decide what you will eat for dinner that night. This is what typically happens when one goes out for dinner at a fancy restaurant. Same routine, different restaurant.
What if every time we went to a different restaurant, we had to remind our brain how to act and what to do? This usually doesn't happen and instead we are used to eating at public places because our brain "remembers" what it is like to be in a restaurant. This is because of schema. Schema is an organized knowledge structure or mental model that we've stored in memory. It helps us simplify our world so we don't have to think over and learn about every situation we are presented with. Without this memory process, we would be constantly confused wherever we went.
Some people suffer with something called Korsakov's syndrome, where they are unable to form new memories. They are constantly having to approach new situations as if it were their very first time. The studies of schema, done by Barlett, help demonstrate that long term memories are constantly being adjusted because of the different experiences we encounter in our lives. Schema is a very important part of our memory system and every day lives.
Next time you go to a restaurant, don't worry about now knowing what to do, because schema is there to remind you!