(GUI Containers) Need help adding players inventory to my new GUI

package com.mcheroesandgenerals.mainmenu.gui;

import com.mcheroesandgenerals.mainmenu.MainMenu;

import com.mcheroesandgenerals.mainmenu.gui.GuiContainerInventory;

import com.mcheroesandgenerals.mainmenu.mainmenuutils.MainMenuNews;

import com.mcheroesandgenerals.mainmenu.mainmenuutils.MainMenuPing;

import com.mcheroesandgenerals.mainmenu.mainmenuutils.MainMenuUpdates;

import net.minecraft.client.Minecraft;

import net.minecraft.client.gui.*;

import net.minecraft.client.gui.GuiButton;

import net.minecraft.client.gui.inventory.GuiInventory;

import net.minecraft.client.multiplayer.GuiConnecting;

import net.minecraft.client.resources.I18n;

import net.minecraft.entity.player.EntityPlayer;

import net.minecraft.entity.player.InventoryPlayer;

import net.minecraft.inventory.Slot;

import net.minecraft.tileentity.TileEntity;

import net.minecraft.util.EnumChatFormatting;

import net.minecraft.util.ResourceLocation;

import org.lwjgl.opengl.GL11;

import java.util.Collections;

public class GuiDecimationIngame extends GuiCustomMainMenu {

    public float fade = 1.0F;

    public GuiContainerDisplayText guiContainerDisplayText = new GuiContainerDisplayText(3, 0, 73, 247, 150, this);

    public ResourceLocation background = new ResourceLocation("mainmenu:gui/backgroundingame.png");

    private final String URL = "http://mcdecimation.buycraft.net/";

    private final String URL2 = "ts3server://ts.mcdecimation.net";

    private final String URL3 = "http://eu.mcdecimation.net:8123";

    public void actionPerformed(GuiButton button)

    {

        if (button.id == 3) {

            Minecraft.getMinecraft().displayGuiScreen(new GuiConfirmOpenLink(this, URL, 20, true));

        }

        if (button.id == {

            Minecraft.getMinecraft().displayGuiScreen(new GuiConfirmOpenLink(this, URL2, 22, true));

        }

    }

    public void initGui() {

        super.initGui();

        initGUI();

    }

    public void initGUI() {

        int x = width / 2 - 173;

        addContainer(new GuiContainerPlayerInfo(1, x + 75, 5, 200, 25, this));

        int y = 1;

        int buttonWidth = 85;

        buttonList.add(new GuiCustomButtonSmall(3, x + 5 + buttonWidth, y + 29, buttonWidth, 10, EnumChatFormatting.BOLD + "Donate"));

        buttonList.add(new GuiCustomButtonSmall(8, x + 91 + buttonWidth, y + 29, buttonWidth, 10, EnumChatFormatting.BOLD + "Teamspeak"));

    }

    protected void drawGuiContainerForegroundLayer(int mouseX, int mouseY)

    {

        this.fontRendererObj.drawString(I18n.format("container.crafting", new Object[0]), 86, 16, 4210752);

    }

    public void updateScreen() {

        super.updateScreen();

    }

    private final int imageWidth = 247;

    private final int imageHeight = 45;

    @Override

    public void drawBackground(int mouseX, int mouseY, float partialTicks) {

        GuiUtils.drawImage(0.0D, 0.0D, this.background, width, height);

        GuiUtils.drawRectWithShadow(0, 0, width, 22, "0x2B2B2B", 1.0F);

    }

}