In summary, create a Word document for your design which includes:

Three entities and each entity should have at least three attributes.

Properly Identify all Primary (Use Solid Underlines) and Foreign Keys (Use Dotted Underlines)

Define the relationships between entities (See examples in Data Model and Database Entities and Relationship Modeling lessons)

Create an entity-relationship diagram (ERD) from the entities. You may use SmartDraw, Visio, Erwin, or even PowerPoint or Word to draw the diagram. Take a screenshot (no need if you use Word) and insert it into the Word document.