Hello Leo!
I took a little bit of time to check out your instagram, and I must say your tenacity towards staying in the habit of drawing seems to be developing well. I saw you got halfway through Inktober, which is waaay better than my first year.
Speaking of that first year, I have some advice for you, because what will trip you up more than anything is assuming that going through the motions-- merely putting pencil to paper and making sure your shapes are right and drawing to make sure something looks right-- will carry you through to the end. Sometimes engaging in that mindset is exactly what you'll need to get going on understanding how to draw, but often it's a little bit of a trap. It was my first year of Inktober that my mindset was exactly like that, but it wasn't until I started picking up the fundamentals that things became much easier.
The first thing you need to understand about understanding how to draw is that the best artists, from my student's perspective, is about understanding what makes things work: stuff like the physiology of your arm when you're drawing, or the rule of thirds, or color theory principles.
Start with this: try drawing a perfect circle with one stroke. If you're anything like I was in my first year drawing class, your circles will be all skillywonk, because at the start of my first session I had a lot of trouble doing shapes like that. My art teacher told me, however, that by not moving the wrist and instead making circular motions using the upper arm and keeping the forearm relaxed, drawing more perfect circles was not only easier to do, but it was a lot quicker. This is the concept of gestural drawing: using the body's natural capacities to move and understanding what will do what, like how holding the forearm and wrist makes drawing circles easier. I should say that SVS's "How to Draw Everything" course goes over the exact same stuff, with demos at the end to demonstrate how the concepts work.
Physiology is only one half of the battle, however, and the other is understanding fundamentals. Thankfully, fundamentals are the things you can discover and pick up by observation. What I mean to say is that the theory of drawing can be learned by watching people work, reading about how art works, and making general observations to see how principles are applied to already-finished work. Rule-of-thirds, for example, is something you can start observing in everything, and it's a fairly accessible-to-learn element of drawing and art in general.
All of this swirls together and coagulates to answer your original question like this: you need to look at work, and you need to make work. You can hear a million theories on how art and illustration works, but unless you just go and make pieces, you won't be able to apply the principles you learn. If you're having trouble absorbing it all, take it one principle at a time, yanno? If you're having trouble drawing objects, take a look at some simple objects and dissect how to draw them. Try getting together some simple objects and drawing them really well to start, and while you're doing those things, just think about the principles you've already learned. It's also important to pick up new concepts and to push yourself at the beginning, especially if you've not got anyone else to push you.
Well! I did not intend to write the wall of text I just wrote, but I hope it works out! Stick with it, man, you'll get better as you go, for sure!