settings.php

<?php
    // This file is part of Moodle - http://moodle.org/
    //
    // Moodle is free software: you can redistribute it and/or modify
    // it under the terms of the GNU General Public License as published by
    // the Free Software Foundation, either version 3 of the License, or
    // (at your option) any later version.
    //
    // Moodle is distributed in the hope that it will be useful,
    // but WITHOUT ANY WARRANTY; without even the implied warranty of
    // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    // GNU General Public License for more details.
    //
    // You should have received a copy of the GNU General Public License
    // along with Moodle.  If not, see <http://www.gnu.org/licenses/>.

    /**
     * Settings for Block news slider.
     * @package    block_mylastforummessages
     * @copyright  2018 DigiDago
     * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
     */

    defined( 'MOODLE_INTERNAL' ) || die;

    if ($ADMIN->fulltree) {

        $settings->add( new admin_setting_configtext( 'block_mylastforummessages/messagelenghtmax' ,
                                                      get_string( 'messagelenghtmax' , 'block_mylastforummessages' ) ,
                                                      get_string( 'messagelenghtmaxdesc' , 'block_mylastforummessages'
                                                      ) , 50 , PARAM_INT
                        )
        );

        $settings->add( new admin_setting_configtext( 'block_mylastforummessages/displaypostnumber' ,
                                                      get_string( 'displaypostnumber' , 'block_mylastforummessages' ) ,
                                                      get_string( 'displaypostnumberdesc' , 'block_mylastforummessages'
                                                      ) , 3 , PARAM_INT
                        )
        );

        $settings->add( new admin_setting_configcheckbox( 'block_mylastforummessages/onlyannoucement' ,
                                                          get_string( 'onlyannoucement' , 'block_mylastforummessages' ) ,
                                                          get_string( 'onlyannoucementdesc' , 'block_mylastforummessages'
                                                          ) , 0
                        )
        );

    }