Make sure you have a dashboard controller, create it first by using "make controller" artisan as laravel do :

php artisan make:controller DashboardController

Then add getIndex() method.

class DashboardController extends Controller {
    public function getIndex() {
        $data = [];
        $data['page_title'] = "Dashboard";
        return view("dashboard", $data);

Create the view /resources/views/dashboard.blade.php:



Last, you have to set the dashboard controller at Developer Area > Appearance > Dashboard Controller