If you're new to programming, jumping from 8kyu to a 6kyu problem isn't ok. What you see in "Your Next Challenge" depends on the value below the language, it could be Random, Rank Up, Fundamentals. You could also click on Kata on the left sidebar and select the language and the kyu lvl. It's hard to explain what you need to do here without spoiling it and I'm not sure if what I can suggest would help you without seeing your code.