[CodeIgniter] สงสัยเรื่อง การทำ register และ ส่ง sendVerificatinEmail ตรงช่วงใน config ว่ามันต้องเป็นยังไง กรอกอะไรบ้าง

 //config email settings
        $config['protocol'] = 'smtp';
        $config['smtp_host'] = 'ssl://smtp.gmail.com';
        $config['smtp_port'] = '587';
        $config['smtp_user'] = $from;
        $config['smtp_pass'] = '*********';  //sender's password
        $config['mailtype'] = 'html';
        $config['charset'] = 'iso-8859-1';
        $config['wordwrap'] = 'TRUE';
        $config['newline'] = "\r\n"; 
        
        $this->load->library('email', $config);
		$this->email->initialize($config);
        //send email
        $this->email->from($from);
        $this->email->to($receiver);
        $this->email->subject($subject);
        $this->email->message($message);
        
        if($this->email->send()){
			//for testing
            echo "sent to: ".$receiver."<br>";
			echo "from: ".$from. "<br>";
			echo "protocol: ". $config['protocol']."<br>";
			echo "message: ".$message;
            return true;
        }else{
            echo "email send failed";
            return false;
        }