4:19 PM, Thursday October 8th 2020
When you do the Draw a Box lessons, it's best to follow instructions to the letter: complete the challenge first than submit your work for review.
But you can always read the text and watch the video of the challenge multiple times; it takes time to absorb all the information.
About your pace: if you're in doubt, slow down. The point of the challenge is to get the most out of it. Better invest one more month in your boxes and finish it with a stronger understanding of 3D space.
PS: I'm almost halfway through the same challenge.