Software engineering nowadays is really complex. There is no way you're going to know what's going on, nobody is.

It's just the more experience you have, the easier it is to figure out what's going on. If you want to learn coding, just start coding.

I will start from something no one mentioned - start with Linux. Windows has its own very "special" ways of compiling stuff, while Linux is very simple. If you start on Windows, you'll probably use IDE which will set up everything for you (cause setting up thing in Windows is messed up), and it will still be a black magic for you how the code transforms into binary.

Many people recommend python, but I would start with C (not C++, C++ sucks). It will give you the understanding of basic concepts like memory management.

Then start using something like javascript, which will get you wide range of libraries, which you can use to build anything.

Then at the end learn how infrastructure works, how are services communicating with each other, how to put your server to the public, learn Docker, set up reverse proxy, run stuff in cloud.