The conceptual model is the most fundamental aspect of the interface, describing the relationship between the interface and the outside world. The purpose of the conceptual model is to draw on the user’s past experiences so they can readily understand basic operations and naturally predict functionality in an application.
A vision describes the goal of the project. It can be emotive and a source of inspiration. For instance, by outlining how the final product makes the world a better place you can draw upon inspiration to create the end goal of your project. Describe the project's final goals. Explain who will use the product, and how he or she will take advantage from it. Make sure your vision is shared between all project stakeholders. Leave room in your vision for creativity and changes. Keep it short.
A good starting-point is the elevator pitch:
Personas can help identify the target users of your application and provide a common understanding among the design and development team. A persona is the representation of a user, based on empirical data. Personas describe the target users, giving a clear picture of how they're likely to use the system, and what they’ll expect from it. The description includes a concise summary of characteristics of the user, their experience, goals and tasks, pain points, environmental conditions and even name.
The KDE usability team has created predefined personas which we highly recommended using for your project.
If you choose to create your own personas, consider the following:
Scenarios illustrate how the users achieve their goals by means of task-orientated examples. It is supplementary to a persona, providing together an efficient method applicable in a wide range of applications.
Use the following guide to help create scenarios:
While thinking about the scenarios, also consider devices of which class(es) the personas would use in that scenario. Currently, Plasma and (some) KDE applications target the following device classes: Desktop/laptop, media center (TV), phone and tablet/convertible. Your application may target other device classes (like eg. in-vehicle entertainment systems, kiosk systems, ...) as well.
A useful template for documenting your personas and scenarios is the Project User Research Template