Object Orientation in PHP, example crud with ajax [closed]

I'm trying to learn PHP Object Oriented, however I'm having trouble finding an example. Can someone show a simple example of the crud case below:

• A class in php, for example, user, in this class has methods that return the user by id.

• All users return.

• inserts the user.

• update the user.

• delete the user.

I also wanted to know how I can call this methods.

In case I will use ajax then I will have to use a php file instantiated the class object.

I apologize for the naivety, but I believe that here I will have the best examples and support in the doubts.

If anyone knows / has any material relevant to this, I would also appreciate it.

What I did:

  <?php
    class Listas{
      public $guid;
      public $eguid;
      public $concluida;
      public $titulo;
      public $descricao;
      public $datecreate;

      function listarListas($db){
        $result = $db->select('cad_listaconf');
        $res = array();
        $res = $db->getResult();

        return $res;
      }

      function inserirLista($eguid, $titulo, $descricao, $datecreate, $db){
        if ($query = $db->insert('cad_listaconf', array('eguid'=>$eguid,         'titulo'=>$titulo, 'descricao'=>$descricao, 'datacreate'=>$datecreate))){
          return 1;
        } else {
          return 0;
        }
      }

    }

?>