The document introduces three tables containing information about customers, products purchased, and suppliers. The customer table includes names, dates of birth, emails, and payment methods for 5 customers. The products table cross-references customers, products, suppliers, categories, prices, and quantities. The suppliers table lists supplier names, locations, days of operation, and delivery days. The document explains that properly structuring this information in a database like Access can help reduce errors, repetition, and make the data easier to search compared to putting it in Excel.