The basis of Schema Theory maps knowledge in related clusters called schema. Cognitive scientists and psychologist sometimes use this terminology in an attempt to map the way we classify knowledge into groups. For example, each person likely has a general cluster of knowledge around the schema of a car. We know it has certain parts like wheels, an engine, seats, and we know that certain parts tend to be located in certain areas. E.g., wheels are located at the base of the car.
Our schemata are influenced by our culture. Most Americans have a Thanksgiving Schema, for example. We have basic knowledge of what Thanksgiving entails and can understand conversations where Thanksgiving is referenced. One need not go into detail about dinner food when speaking with an American about the Thanksgiving Day parade. This is because most people have a basic knowledge or schema on what Thanksgiving means. Referencing "Thanksgiving" only serves to add context to a conversation in this example.
When we are creating learning materials designed to advanced learners' understanding of a subject. It's important to use examples that draw from familiar schema learners are likely to be familiar with. If examples are relatable and familiar, learners are less likely to get hung up on unimportant details and potentially more likely to learn on deeper levels as they relate new information with old knowledge.