How to specify path for the folder in Windows - php

Question

I have a form that lets the user to upload files to the server, but I did not know how to write the correct path for that folder in the server which I want the files to be store in, also how to get the path for specific file to download later.
The path in the server:
/public_html/upload_files
The error I am getting:
Warning: move_uploaded_file(upload_files/project_guidelines.pdf):
failed to open stream: No such file or directory in
D:\sites\dwts.com\public_html\website\creat.php on line 50 Warning:
move_uploaded_file(): Unable to move 'C:\Windows\Temp\php14AC.tmp' to
'upload_files/project_guidelines.pdf' in
D:\sites\dwts.com\public_html\website\creat.php on line 50 Error
uploading file
Code:
$len = count($_FILES['Attachment']['name']);
for($i = 0; $i < $len; $i++) {
$uploadDir = 'upload_files/';
$fileName = $_FILES['Attachment']['name'][$i];
$tmpName = $_FILES['Attachment']['tmp_name'][$i];
$fileSize = $_FILES['Attachment']['size'][$i];
$fileType = $_FILES['Attachment']['type'][$i];
$filePath = $uploadDir . basename($_FILES['Attachment']['name'][$i]);
$result = move_uploaded_file($tmpName,$filePath);
if (!$result) {
echo "Error uploading file";
exit;
}

Answer 1

$uploadDir = 'upload_files/';
Where is the drive? Its Windows, so it needs a drive:
$uploadDir = 'c:/upload_files/';
You can't give a partial location to the second argument of move_uploaded_file...it needs a full path.