How to add a achievement

So i finnaly figured out how to do this but it still gives me a error.

Is this the good line of code to make a new achievement. And how do i put it in my new achievement tab?

public static Achievement Dirt;

@EventHandler

public void modsLoaded(FMLPostInitializationEvent event)

{

Dirt = new Achievement(27, "Dirt", 0, 0, Blocks.dirt, null).isAchievement();

this.addAchievementName("Dirt", "Dirt.. Really?");

this.addAchievementDesc("Dirt", "You just found a piece of dirt..");

}