The downfall of low fidelity prototypes is that they are not meant to allow the user to explore very much. There is usually one process to be tested or experienced. Therefore the user should be guided towards these specific tasks without detailed instructions. Instructions can often guide the user so much that they do not fail. As said in lecture, “You want to see how they fail, and how they got out of it.” The ideal instructions do not reveal the task design, vocabulary, or structure.
Here are some guidelines for developing a usability test: http://www.usability.gov/how-to-and-tools/methods/planning-usability-testing.html
Other times, users should feel as though they are in control and have the freedom to choose between multiple functions, so that they can recommend improvements. This way, users will be able to recognize errors that the designer did not consider. For this reason, there should also be undo buttons and error pages at the ready during a usability test.
An example of a usability test with a paper prototype: https://www.youtube.com/watch?v=9wQkLthhHKA
Contributed by Amelia Miller, Maria McLaughlin, and Maia Suazo-Maler.