Create a new OpenFL project:
openfl create project ProjectName
cd ProjectName
openfl test neko
You can drop the converted Haxe code into the “Source” directory of your new project, and can run it again.
I also recommend having Visual Studio Code and the Lime extension installed, so you have a good Haxe code editor. There are other options available, but that’s what I use 
There will probably be minor compilation issues. I just helped someone on this thread with some. This older blog post may help with some issues you’ll experience, and of course, there’s the forums here and Discord for help as well.