This haxe engine can make the online game?
Yes it can.
Can it have a tutorial?
If someone writes it, it can.
Ok thank you
There are multiple game engines made with the Haxe language. HaxeFlixel is a 2d game engine made with Haxe, and has a lot of examples, tutorials and users. If you want to do a 2d game, it can be the most easy to start : https://haxeflixel.com/