Protecting the directory for your files should be one of the first steps after installing Filr. Go to Filr->Settings and you will find all settings related to the directory protection.
Choose a protection mode for your newly-created directory. If you are using an apache server you can choose “htaccess” protection. If you are using another server type (like Nginx or windows) you should use index.php to successfully protect your files.
You can check the protection with the link below.
Most servers already have everything that is needed to run Filr. It only needs a modern PHP version, the ability to zip files, and a decent upload limit to run. However, to make sure you are not getting into any trouble I integrated a little diagnostics tool for you:
Once you selected a protection mode, set a name for your directory, save your settings and you are ready to use Filr to create protected file-and document libraries.