I tried to dive into event-driven programming with fltk. There is a tutorial for writing a simple text editor( https://www.fltk.org/doc-1.3/editor.html ).
But this tutorial is a little bit gappy.
I don't know how I must bake the stuff together for getting a working program.
So specifically which part is not working? Is the program not compiling, or is it a particular feature that isn't working?
If this is your first time trying out the library, regardless of that that library is, have you tried first to make a simpler "hello world" app compile and run, and then slowly build on that?