What kinds of information and insights did it give you about the usability of the prototype?

Userts’ perform tasked more naturally and respond more directly. Therefore, the observer could learn the detailed performance of the user to check the user’s mood, minor movements. Think-aloud is a easy way to accurately understand users behavior and why they feel the way.
What aspects of the technique worked well or were frustrating?

Users in the use of the process will be emotional. For example, task3 is mission that the user need to find a book in library website and some users dislike library website. Therefore, they would irascible when they use this website.