php/WordPress/Ajax Button call a php script

I’m just beginning to learn PHP and I am developing a WordPress plugin. But I have a problem. When I press a button, I want it to call a PHP script where I have a different SQL request to execute and others things without changing page. I know I need to use Ajax but I don’t understand how use it and where I write it. Could you help me please?

index.php is where I have a function that prints a list with checkbox and the button to execute the script createInsert.php

PS: Sorry for my bad English.

index.php

 <?php
   public function pref_liste_checkbox(){
        global $wpdb; 

        print '<h3>Composition de la liste synthetique</h3>';
        print '<form method="POST" action=" "><table border="1"><tr><th>Attributs</th><th>Choix</th></tr>';

        $resultat= $wpdb->get_results("SELECT * from wp_frm_fields ",ARRAY_N); 

        foreach ($resultat as $post) {      
           print'<tr>';
           echo '<td>'.$post[2].'</td>';
           echo"<td><center><input type='checkbox' name='choixP[]'value='".$post[0]."'></center></td>";
        }

        print '</tr><input type="submit" name ="execute"value="execute"></table></form>';
    }
?>

createInsert.php

<?php
     //if the table exist =1 
    if(FrmStatisticsController::table_ok('testWP','wp_users')==1){

    ?>
            <script type="text/javascript">

                    var r = confirm("Voulez-vous vraiment mettre à jour les attributs de la liste synthétique?");
                    if (r == true) {

                        <?php
                                ///////////CLEAN LA TABLE//////////
                                ////////////INSERT INTO/////////

                        ?>
                        var f = alert("MàJ réussie !");

                    }else {
                                ///////////Aucune ActionNo Action////////
                    }

            </script>
    <?php

    } else (FrmStatisticsController::table_ok('testWP','wp_users')==0){

    ?>
            <script type="text/javascript">

                    var r = confirm("Voulez-vous sauvegarder les attributs de la liste synthétique?");
                    if (r == true) {

                        <?php
                                ///////////CREATE TABLE//////////

                                global $wpdb;
                                $nom_table = $wpdb->prefix .'choix_attributs_liste';
                                $sql = "CREATE TABLE $nom_table ( mytable_id bigint(20) unsigned NOT NULL auto_increment, att_name varchar(255), att_id bigint(20),PRIMARY KEY(mytable_id));";
                                dbDelta($sql);

                                ////////////INSERT INTO/////////
                        ?>

                        var f = alert("Création et insertion des n-uplets réussie!");

                    }else {
                                ///////////Aucune ActionNo Action////////
                    }

            </script>
    <?php
    }