All you need to do is download `index.php` in this repository and put it in a folder on your web server. You need to make sure that PHP can write to that folder though. However, you can deny write access to the file itself since there is no automatic updating function built in yet.
To configure it, open your downloaded copy of `index.php` in your favourite editor - the settings can be configured at the top of the file. There are extensive comments that explain what each option does. Make sure that you change the allowed usernames and passwords! If you need more help, don't hesitate to open an issue on this repository or contact me.