I need help improving my software engineering skills

Hi all, I made a post in this subreddit a few months ago wanting to learn front-end development and I got amazing advice. Someone pointed me to freecodecamp and while it was a slow, it allowed me to understand front-end development like JS for me to practice on my own. I've toyed around building websites with HTML, CSS, and JS and I've grown fairly confident in the three. However, I took a look at the node.js and I'm completely lost. There are a lot of server stuff like GET and POST requests that I just do not understand. I tried googling stuff like "what's a server" and "how do servers work" and while I got some answers, I'm still lost. I guess my question is: Given that I know HTML, CSS, JS, and many other languages like python, java, c+, GoLang, etc, how do I combine all these skills to start actually creating software? How do I go about learning what I need to learn to use node.js and other libraries? If you have any pointers, please shoot them my way!

edit: node.js is a framework, but you get the idea