PHPMailer install?

I am trying to set-up a ‘forgot-password’ function and my script do have all what i need, but i don’t know how to set-up PHPMailer for it. I already have PHPMailer script installed

Where i put this script?

<?php
use PHPMailerPHPMailersrcPHPMailer;
use PHPMailerPHPMailersrcException;

require("Exception.php");
require("PHPMailer.php");
require("SMTP.php");

$mail = new PHPMailer();
$mail->IsSMTP();
$mail->Mailer = "smtp";
$mail->Host = "mail.mail.com";
$mail->Port = "465"; // 8025, 587 and 25 can also be used. Use Port 465 for SSL.
$mail->SMTPAuth = true;
$mail->SMTPSecure = 'tls';
$mail->Username = "[email protected]";
$mail->Password = "";

$mail->From = "[email protected]";
$mail->FromName = " Mailer";
?>

I am using IIS