There's 2 ways. First is the reading other people's code method. You find something that's open source, like an existing app and read through the code to figure out how to make changes yourself, usually through trial and error. In the process of this you refer to documentation and books/tutorials.

The other is you work through a text or course before hacking stuff together. Most people don't have the will to do this, they lose interest after one or two chapters unless they are either paying for it (school) or they already have been hacking some program and want to know more, which keeps them interested in the book. There are endless book and course suggestions, pick something with a lot of exercises (most edx/moocs have too few) like PAPL https://papl.cs.brown.edu/2018/index.html only because programming is often learn by doing. No local installation is needed at first either https://code.pyret.org/