Once you have a better understanding of our data, you need to define your RDBMS schema.
A database's schema describes its structure in a formal and logical language. It describes the relationship between entities. For example, entity X connects to Y. Then, entity Z further interacts with Y and X.
You can look at the relationship between X and Y, and then seem how that changes once you apply Z's data.
If it sounds confusing, here's an example. A librarian wants to see which user has borrowed out what book, and for how long. X can be users, Y can be books, and Z can be books currently out on loan. Relational Databases draw conclusions between blocks of data (entities).
Eventually, once the database schema is ready, you can install it into your RDBMS, and then look for relationships between entities.
In an RDBMS, entities are another name for tables.
And tables are similar to tables in a spreadsheet.
A relational database organises data into tables, and the schema describes relationships between the records stored in those tables.
Still confused? Remember that a Relational Database has at least three tables - these are called entities - and that when you search in a RDBMS you're drawing relationships between the data contained in the tables.
Here's the library example in more detail: if you're a library manager, you can separate book data into Users, Books, Books out on loans, authors, and categories. You can list each of these topics as a table (see below).