The key with nodes is to think of each node as an operation. you are doing a series of operations and passing the output of those operations onto the next.
There are a number of tutorials out there for learning the basics, but the best thing to do is to start exploring.
I have been participating in nodevember myself, and you can find my thread here:
I share all of the .blend files for all of my daily exercises, under a CC0 license. Download them, check them out, tweak some knobs and see what happens. if it breaks and you don’t know how to fix it again, just revert the file and try again.
If you hover over a node and press the M key, it will mute that node, which can be a quick way to toggle and see what the effect of that node is. Sometimes it’s a basic tweak, sometimes it combines things, sometimes it is an input texture.
Primarily, just have fun. See what you can do with it, and feel free to ask questions. There are a lot of node wizards on this forum with a lot of knowledge.