GuiMenu gui = xaGui.createMenu("&a&lExample GUI", 3);
gui.fillSlots(new HashSet<>(Arrays.asList(0, 1, 2, 3, 4)));
gui.fillSlots(new HashSet<>(Arrays.asList(12, 13, 14)), new ItemStack(Material.DIRT, 64));
GuiButtonInterface closeButton = new GuiButton(new ItemStack(Material.BARRIER, 1)).setName("&cClose").withListener((event) -> {
player.closeInventory();
}).setLore(Arrays.asList(" ", "&aClick to close Inventory"));
gui.fillSlots(gui.getCurrentPageIndex(), new HashSet<>(Arrays.asList(21, 22, 23)), closeButton);