Solved Scoreboard doenst appear

Hey I'm trying to make a scoreboard for my plugin for 1.13. But it doesn't appear in game when you join the server. There is no error in the console so I can't really figure out what's wrong. And yes the class is registered This is my code:

Code (Java):

public class Scoreboard implements Listener {

    @EventHandler
    public void onJoin(PlayerJoinEvent event) {

        ScoreboardManager manager = Bukkit.getScoreboardManager();
        Objective objective = manager.getNewScoreboard().registerNewObjective("test", "Test", "dummy");

        Player p = event.getPlayer();

        objective.setDisplayName(Gijs.cc("&a&lScoreboard"));
        Score score = objective.getScore("&aTest");
        score.setScore(10);

        objective.setDisplaySlot(DisplaySlot.SIDEBAR);
        p.setScoreboard(manager.getNewScoreboard());
    }
}

 

So i should use #getMainScoreboard instead?

 

I don't really use scoreboards and could not find any 1.13 tutorials. Could you help me with how to fix it bacause is dont understand

 

It says i should use this code but then it doesn't work. There is still no error.

Code (Java):

 
public class Scoreboard implements Listener {

    ScoreboardManager manager = Bukkit.getScoreboardManager();
    Objective objective = manager.getNewScoreboard().registerNewObjective("test", "Test", "dummy");
    Scoreboard board = (Scoreboard) Bukkit.getScoreboardManager().getNewScoreboard();

    @EventHandler
    public void onJoin(PlayerJoinEvent event) {
        Player p = event.getPlayer();

        objective.setDisplayName(Gijs.cc("&a&lScoreboard"));
        Score score = objective.getScore("&aTest");
        score.setScore(10);

        objective.setDisplaySlot(DisplaySlot.SIDEBAR);
        p.setScoreboard((org.bukkit.scoreboard.Scoreboard) board);
    }
}

 

Thanks! I changed it and this worked