How to change from mysqli to PDO?

Question

PHP

Good evening! Help to remake the connection from mysqli to PDO.
I am going through a tutorial about MVC, but it contains a connection to mysqli, since I started with PDO, I want to continue with it. What I tried to do looks very bad, and it does not work as it should.

class DB {

    protected $connection;

    public function __construct($host, $user, $password, $db_name){
        $this->connection = new mysqli($host, $user, $password, $db_name);

        if( mysqli_connect_error() ){
            throw new Exception('Could not connect to DB');
        }
    }

    public function query($sql){
        if ( !$this->connection ){
            return false;
        }

        $result = $this->connection->query($sql);

        if ( mysqli_error($this->connection) ){
            throw new Exception(mysqli_error($this->connection));
        }

        if ( is_bool($result) ){
            return $result;
        }

        $data = array();
        while( $row = mysqli_fetch_assoc($result) ){
            $data[] = $row;
        }
        return $data;
    }

    public function escape($str){
        return mysqli_escape_string($this->connection, $str);
    }

}