How to add smtp host to send mails with this phpmail script - php

Question

I want to send mails using this PHP MAILING script but through SMTP and not through sendmail because my host rejects all emails as spam and I don't check my spam folder as its heavy loaded with spam emails daily.
I just want to know where to put the code which will use my SMTP logins to send mails using this php script instead of using sendmail/
I tried adding some things like
$host = "smtp.gmail.com";
$port = "587";
$username = "testtest#gmail.com";
$password = "testtest";
But these didn't worked, actually it broke the whole code itself,
Edit: I also tried adding this, reading an answer from another answered question here, and it also broke the code itself but didn't work.
$smtp = Mail::factory('smtp', array(
'host' => 'ssl://smtp.gmail.com',
'port' => '465',
'auth' => true,
'username' => 'johndoe#gmail.com',
'password' => 'passwordxxx'
Original Code
<?php
$errorMSG = "";
// NAME
if (empty($_POST["name"])) {
//only shows if prevent default fails (js in index.html)
$errorMSG = "Name is required ";
} else {
$name = $_POST["name"];
}
// EMAIL
if (empty($_POST["email"])) {
//only shows if prevent default fails (js in index.html)
$errorMSG .= "E-mail is required ";
} else {
$email = $_POST["email"];
}
// MESSAGE
if (empty($_POST["message"])) {
//only shows if prevent default fails (js in index.html)
$errorMSG .= "Message is required ";
} else {
$message = $_POST["message"];
}
// change this to fit !
$EmailTo = "demo#domain.com";
$Subject = "New Message from MENTOR";
// prepare email body text
$Body = "";
$Body .= "Name: ";
$Body .= $name;
$Body .= "\n";
$Body .= "Email: ";
$Body .= $email;
$Body .= "\n";
$Body .= "Message: ";
$Body .= $message;
$Body .= "\n";
// send email
$success = mail($EmailTo, $Subject, $Body, "From:".$email);
// redirect to success page
if ($success && $errorMSG == ""){
echo "success";
}else{
if($errorMSG == ""){
echo "Somethin went wrong...";
} else {
echo "An error has ocurred!";
//echo $errorMSG; Enable if you want full details of php error
}
}
?>