Ralkage See here: http://flarum.org/docs/extend/start/
Getting Started
Alright, enough chit-chat — let’s jump right in and make a basic “Hello World” extension for Flarum. You’ll need to have Flarum up and running to do this, so if you haven’t installed Flarum yet, go and do that now.
All done? Okay. We’ll start by giving your extension a place to live. Browse to the extensions directory and create a new folder. Give it a kebab-case name with the format: vendor-package, where vendor is the vendor name and package is the name of your extension.