4:34 AM, Sunday August 30th 2020
Any of the above. You can move on to the next lesson, but if you end up finishing eg. Lesson 2 before eg. 250 Boxes gets feedback, it's probably best to wait for 250b feedback to come in first so you don't propagate any mistakes/bad habits too far down the road.
But it's also a good time to do fun art (250 Boxes is heavy going - nice to have a break!) or give feedback for Lesson 1 or anything you've already been marked on.
I'm waiting for 250 Boxes myself, so I'm doing all the above - taking my time on Lesson 2, doing lots of fun art, and giving feedback here.
ETA - Forgot to add: if you're on the Discord server and waited 1-2 weeks but haven't gotten community feedback yet, you can ask on the relevant server channel. Someone is usually willing to mark your homework if you return the favour by doing some community feedback here.