@Kylotan: have you checked out this
extensive list of docs, tutorials, examples, and source code on the Flixel github wiki? You should be able to find enough there to get started with basic projects, and learn how game objects work and function.
Once you've done that, if you visit the
Flixel category at FlashGameDojo, you will find a whole bunch of example code snippets that describe how to achieve different things (eg. "Collision", "Fix object on screen", or "UI, HUD or Status Overlay").
Just ctrl-F some keywords and you should be able to find what you want. Once you've got a handle on the basics, it's just a matter of finding out more specific things that you want to achieve, which sometimes there are built-in methods for, but sometimes there are not. In either case, giving the
Flixel help forums a quick search should pop up an answer, and if not posting the question should result in a fairly quick reply if your question is not too complex.
Good luck