One important piece for the design process is the creation of the user personas. This step is essential, so you as a designer can understand different case scenarios for the different type of users that your app is intended for.
A user persona is the creation of an imaginary character based on what we think is a typical end-user of our app. The description of the persona must include personal details, goals, and concerns of the character. Very similar to the work that screenwriters do when they are creating characters for their screenplays.