Model files in CI4

Your files and code should look something like this:

Entities/ComuniEntity.php

PHP Code:

<?php
namespace App\Entities;

use CodeIgniter\Entity\Entity;

class ComuniEntity extends Entity
{
    protected $datamap = [];

    /**
    * Define properties that are automatically converted to Time instances.
    */
    protected $dates = ['updated_at', 'created_at'];

    /**
    * Array of field names and the type of value to cast them as
    * when they are accessed.
    */
    protected $casts = [];
} 


Models/ComuniModel.php

PHP Code:

<?php
namespace App\Models;

use CodeIgniter\Model;
use App\Entities\ComuniEntity;

class ComuniModel extends Model
{
    protected $table = 'AA_Tabella1';
    protected $returnType = ComuniEntity::class;
    protected $allowedFields = ['column_1', 'column_2', 'column_3'];

    public function Leggi(string $Lingua = '') 
    {
        if (!empty($Lingua)) {
            return $this->where('Lingua', $Lingua)->first();
        }

        return $this->findAll();
    }
} 


Controllers/Prova1.php

PHP Code:

<?php
namespace App\Controllers;

use CodeIgniter\Controller;
use App\Models\ComuniModel;

class Prova1 extends BaseController
{
    public function index(string $Lingua = 'en')
    {
        $modello = new ComuniModel();

        $Dati = [
            'Lingua' => $Lingua,
            'ListaLingue' => $modello->Leggi($Lingua),
        ];

        echo view('pagprova2', $Dati);
    }
} 


I hope this will help you to get one "module" going and to continue on other 49...ish