Here is a simple relational model. For example, each exam subject has several papers (left two boxes above). .
You have already seen this in action here. This takes you to the subject entry for Maths.
In this way you cen navigate around the whole database structure.
This model needs modification if the same exam papers apply to more than one subject. For example both the Maths and Physics courses might use a common paper. So the course may have several papers and the papers can be used by several courses. This is called a many-to-many relationship. You deal with this by creating another file (called a join table) that has one record for every subject/papers combination.