What level and intensity are you looking for?
Clearly defined class levels are important when establishing expectations for students. What level are you? Are you looking to take a step back, or maybe challenge yourself? Work within your comfort zone and book a class that is best suited for your current understanding of the practice of yoga. Intensity doesn't not necessarily reflect difficulty, as beginner level yoga poses can also be high-intensity (ex. holding a high lunge for a longer period of time can still make your muscles burn). If ever you feel unsure about what the levels and intensity means, you can always come back to this resource.