YourPlugin.java

package com.example.spawnerprovider;

import net.brcdev.shopgui.provider.spawner.SpawnerProvider;
import net.brcdev.shopgui.provider.spawner.YourSpawnerProvider;
import org.bukkit.plugin.java.JavaPlugin;

public class YourPlugin extends JavaPlugin {

    @Override
    public void onEnable() {
        setupSpawners();
    }

    private void setupSpawners() {
        SpawnerProvider yourSpawnerProvider = new YourSpawnerProvider().hook(this);
        ShopGuiPlusApi.registerSpawnerProvider(yourSpawnerProvider);
    }
}