Human computer interaction is about evaluating and designing interfaces on digital devices. It involves a considerable element of psychology, as it is about how humans perceive and interface. A common misunderstanding is that this standard might be about building an interface; it is much easier to do this assessment critically reviewing an existing interface, as the worst person to evaluate an interface is the person who designed it. The challenge for many students is to step back from the device and think about what challenges and confusion it might cause for the user, which requires a good level of sympathy for a "typical" user!
This topic is covered in detail in the Human Computer Interaction chapter.
The first section of the chapter introduces the big ideas around HCI, and the second section sensitises students to the issues around users and tasks. Some general issues and approaches are raised in the interface usability section, and then the idea of usablity heuristics is introduced. These heuristics are the key to addressing the standard, but the preliminary understanding is needed to avoid just treating them in isolation.
A trap with this standard is to describe the interface based on its specifications (screen size, camera resolution, battery life, or even claims of being "user friendly" in the advertising). That is why the "Think aloud protocol" and "Cognitive walkthrough" are important, as they help the evaluator to see an interface through a users' eyes. The heuristics provide a solid internationally used framework to make well-founded observations about the interface.
The scope of the interface that is evaluated should be kept narrow. A simple app like a stopwatch or alarm clock, or other "widget", will usually have more than enough to evaluate, as it isn't so much about the number of buttons on display, but all the states that the interface can get into, and what common sequences of actions are for users. Avoid large systems such as an entire word processor (just the font choice dialogue in a word processor would be enough) or an operating system (such as Windows vs MacOS.)
Where the standard calls for Heuristics to be used, you should use the 10 listed in usability heuristics section, which were originally published by Jakob Nielsen. (Other sets of heuristics exist, but these ones are widely used and fairly straight-forward to apply.)