In general, the official Pipelight installation instructions are good: http://fds-team.de/cms/pipelight-installation.html
However, one important prequisite is to enable xattr on your file system. You need to edit /etc/fstab, and look for the main filesystem (which likely has a type of ext4). Under the
Then remount the filesystem: sudo mount / -o remount
Without xattr enabled, Netflix will throw a DRM error.
Then proceed to install Pipelight per the official instructions, using the multi-plugin method and the Silverlight 5.0 option.
You aren't done yet! Whichever browser you use, you will need to use a User Agent String change extension to make the browser look like Firefox on Windows. Otherwise, the Netflix site will complain about you not being on one of their supported platforms.
I have read reports that Pipelight/Netflix does not work too well with the Firefox browser itself. I used Chromium instead.
Using the fullscreen mode on Netflix and then going back to regular mode crashes the browser and the plugin, at least for me.