Dev AddOn

Creating yourself a MBedwars Add-On isn't that hard as you thing.
But first of all make sure that your plugin.yml is depending MBedwars.
Example:

name: MyFirstMBedwarsAddon
version: 1.0
main: com.me.MyFirstMBedwarsAddon.Main
depend: [MBedwars]

After that is done create a new de.marcely.bedwars.api.BedwarsAddon object.
Example of a Main class:

package com.me.MyFirstMBedwarsAddon.Main;

import org.bukkit.plugin.java.JavaPlugin;
import de.marcely.bedwars.api.BedwarsAddon;

public class Main extends JavaPlugin {
   public BedwarsAddon bedwarsAddon = new BedwarsAddon(this);
}

You can skip the creating of this object if you don't want to create commands.
Here is an example of creating a command:

bedwarsAddon.registerCommand(new BedwarsAddonCommand("testcommand", "<arg1> [arg2] [arg3]"){
   public void onWrite(String[] args){
      // do something
   }
});

That's it!