Node based projects? Getting a better understand for nodes

hey there, I’ve been using blender for six months and it’s been quite the journey so far with all I’ve had to learn. but I’ve run into a problem. it seems in those 6 months Ive yet to get a better understanding of nodes and how to use them properly or just how they work because it seems to me every time I do a project I run into a roadblock because of my lack of understanding of nodes and materials. I usually follow tutorials on how to do something but they usually don’t explain why they put a certain node there. follow tutorials blindly doesn’t really help anyone get better at something. is there any node and Materials based projects or course both free and paid I could do in order to get a better grasp on the texturing(nodes) side of 3d?

any resources or anyone who can tell me their experience of learning nodes would help me greatly. thank you.

This is the best coverage of nodes I’ve seen so far:

The idea is to combine and tweak all sorts of inputs to get what you want. If you know about Photoshop layers, it’s kinda the same thing.