The Google Nexus User manual in PDF is not available yet from Google Nexus 5 Support site.
Sprint Nexus 5 owners can download the Quick start Guide,Nexus 5 Safety & Warranty from LG Official website.
You can download the free guide from Google’s Nexus support site, or from Google Play Books. The total 53 pages quick start guide gives you a good overview of how to use the KitKat flavor of Android.
Download Google Nexus 5 Guide from Google Support Site:
Download Google Nexus 5 Guide from Google Play Books: