This is just another haxelib if we consider the installation process. Quite straightforward in that regard.

haxelib install flixel

Well, that does not end there. With it comes some supporting libraries and they are mandatory to install. These are as below,

flixel-tools
flixel-templates
flixel-demos
flixel-addons

With those installed, one is good to go with haxeFlixel.
The first thing to do is setup the environment. For that simply run the command as

haxelib run flixel-tools setup

Now, if you just run

haxelib run flixel-tools

that will display the options available for this command.
Once setup is done, the command “flixel” can directly be invoked, though the full command is also available as “haxelib run flixel-tools” . While its suggested that one use the shortest command, I personally feel to use the long one.

Now if at all one needs help, just type help before the command as below

haxelib run flixel-tools help template

Well, next is to create some sample projects. Those would be done with the command

haxelib run flixel-tools create

Once run, the command prompt will ask you which demo to create, just put in the number, which ever you want and that will be created.

Finally to create a new project, the command is

haxelib run flixel-tools template -n "HelloProject"

That will create a new HaxeFlixel project.

Happy Coding.