Schemas are mental structures that contain information on an aspect of the world. They help us to understand the world around us.
A behavioural schema is a schema of how to do a behaviour, for example, standing in a line.
A cognitive schema is a schema on how to do cognitive processes, for example, mental multiplication.
As a child progresses through life and have interactions with the environment and gain experiences, their schemas will also develop. This is called discovery learning.
As schemas develop, it leads to cognitive development.