Handling file uploads can be a little bit of a ticky concept to learn for developers just starting out, so it's good to have resources like this to look to for an introduction.

The post gives you a basic version of the two necessary parts for the upload - the HTML for the form and the PHP script to handle the uploaded data. Their sample script simply takes in the file and moves it over to their "/var/www/uploads" directory while ensuring it's a valid upload and that it could be moved.

It's nothing fancy, and there are some other considerations that need to be made for the uploads (like limiting the file type), but it's a place to start.