I recomend start with the tutorial of haxeflixel:
And have the demos and Snipets, at hand. In the case of HaxeFlixel the better material is in the page itself.
Check Itch.io it's similar to steam but more oriented to developers, the forums of there(and this one to)
And try make small demos that you can use as reference(the work of other is useful but ever is more fast work with you own logic) for example a sprite that move of a place to another. or taking paper please, make a sprite do something like change color at being click.
I recoment divide the thing you want to do in the smaller part posible program that and from it add the rest one by one. Programation is much of experience the better way to learn it is test and error(and you gonna do it much anyway). And Try to define the most posible what you gonna do before start to program(is not something that easy as it sound)
Note: I don't recomend you use Haxe develop eviroment, currently have error(derivated of flash developer) in the appman that is use to easy download the templates of haxeflixel, the only way to fix it is seaching and edit a file from the program resources.
Thanks for your answer. It helped me a lot.