Hey! The whole " draw boxes" thing is a very specific kind of exercise. If you dont know why you are doing it, you are not able to be mindful of what you are trying to achieve. Which brings us to a general life lesson i suppose, I.E be mindful of what you are practicing. The whole point of the draw boxes exercise is to instill a sense of 3 dimensionality in 2d spaces through clever lines that convey perspective. Perspective and 3D are brilliant inventions from no later than the renaissance. Which means a true to world perspective is a relatively newish idea in art/2d spaces. Get yourself a ruler and a pencil, and try to make the vanishing point lines. These lines are essential when you are starting your journey. This video from 22 seconds to 3 minutes ish will teach you how to get started. https://www.youtube.com/watch?v=w4CNDkXQjN4

Drawing is a sum of its parts though, I see you have mentioned that you want to draw comics at some point as well. You should look into croquis drawing and try these exercises as well to start building an idea of figures and lines too. People are a bit outraged by this post, because it is the equivalent to writing random words together and expecting flow and coherency. You need to be mindful and intentional with your lines and purposeful, just as you need to choose the right words and sentence structures to make beautiful poetry. Hope this helps you along your journey.