Testing low-fidelity prototypes is an essential part of UX research, as it allows you to gain feedback and insights from users and validate or invalidate your assumptions. There are various ways of testing low-fidelity prototypes, such as user interviews, user surveys, and usability testing. User interviews are a qualitative method; you can ask open-ended questions about users' needs, expectations, preferences, and experiences with your prototypes to understand their pain points, motivations, and goals. User surveys are a quantitative method; you can ask closed-ended questions or ratings about their satisfaction, usability, or desirability with your prototypes to measure and compare the performance of your prototypes. Usability testing is a mixed method; you can observe users performing specific tasks or scenarios with your prototypes and measure their success, errors, time, or feedback to evaluate the functionality and usability of your prototypes.