the database is whole in question marks instead of russian words in mysql

Question

Can someone explain to me how to include mysql_set_charset('UTF8',$link); inside this code? i've tried few common things. The most hardest one is that i've got

<meta charset="UTF-8"> 

in index.php

 <?
        
        $spreadsheetId = '1FfRc7w35oD3oaf4vy_r2srAZihNPHb4qDJzCZH9AQrA';
        $sheets_name = "Report";
        
        define('DBHost', 'localhost');
        define('DBPort', 3306);
        define('DBName', 'u1********lt');
        define('DBUser', 'u1********lt');
        define('DBPassword', '*************');
        
        
        include __DIR__.'/dbdriver/PDO.class.php';
        $DB = new Db(DBHost, DBPort, DBName, DBUser, DBPassword);
        
        function view($data){
            echo "<pre>";
            print_r($data);
            echo "</pre>";
        }
        
        ?>