Hey there, Naf! Glad to see you’re enrolled in the Basics Course! 
About halfway through the second chapter of Basics, in the “Line” module of the course, there’s a lesson on Learning to Sketch from Imagination. Here! https://www.proko.com/course-lesson/project-learning-to-sketch-from-imagination/assignments Just because this lesson is up ahead, doesn't mean you have to wait until you reach that stage to start drawing from imagination! Feel free to sketch from your imagination as much as you want, and the more the better! You want to spend at least as much time drawing for fun as you spend learning how to draw. So go right ahead and start sketching from imagination! As for Level 1 and 2, it’s best to tackle them one level at a time. If you’re just starting out, stick with the level 1 assignments until you’ve made your way through the course, or until you feel like you’re ready for a challenge. If you feel particularly compelled to try a level 2, go right ahead and give it a shot, no harm, no foul! As long as you’re having fun putting the effort into the process, you’ll start to see your skills develop quickly! Looking forward to seeing your work in Basics!