how to resolve Notice: Trying to get Property of non-object and delete a PHP PDO record

Question

I have the following function to delete a record:

   //FUNÇÃO PARA LISTAR TODOS OS USUAROS
       public function ListarUsuarios()
       {

        $stmt = $this->conn->prepare ("SELECT *FROM N00_Usuario");
         $stmt->execute();
        while($lista= $stmt->fetch(PDO::FETCH_ASSOC)){
            echo"<tr>";
            echo "<td><input type='checkbox' name='checkbox[{$lista->id}]'/></td>";

             echo" <td>{$lista['NomeUsuario']}</td>";
             echo" <td>{$lista['EmailUsuario']}</td>";
           echo"</tr>";

        } ; 

       }
    //FUNÇÃO PARA APAGAR
           public function Apagar()
       {
        $stmt = $this->conn->prepare("DELETE FROM N00_Usuario WHERE idUsuario = :id");
               $stmt->bindParam(':id', $id); 
               $stmt->execute();   
        }   

And in the other Home.php file I have the following code:

 <section class='statis text-center'>
           <table class="table table-hover">
              <thead>
                 <tr>
                    <th>#</th>
                    <th>Usuario</th>
                    <th>Email</th>
                  </tr>
              </thead>
            <tbody>
                 <tr>
       <td><?php  echo $auth_user->ListarUsuarios();?></td>        
                 </tr>    
            </tbody>
            </table>
            <a href="delete.php?id=<?php echo $auth_user->Apagar();?>" onclick="return confirm('Tem certeza de que deseja remover?');">Remover</a>



       <button type='submit' class='btn btn-primary' name='id'>Adicionar</button>
       <button type='submit' class='btn btn-info' name='id'>Editar</button>
<div>


</div>
        </section>

Does anyone know how to get out of this? I can’t pass an id to be able to delete a selected item.