How do I install shared games using the Steam Family Sharing feature?
Solution 1:
You are probably applying one of the many games list filters (ie: installed games) - choose the game library you wish to view from this menu at the top of the steam window (the same way you would filter to show only installed games) and this will present you the available games from that library:
(On a train at the moment so higher quality screenshot will be added later)
Solution 2:
Per the FAQ, it seems the account that is enrolled in the beta must be logged in on a shared machine (i.e.- a machine you have access to as well). Games from that accounts library must already be installed on the machine. And that account must have authorized your user for shared library access.
It seems Family Sharing is just that, intended for multiple gamers in the same household to play the same games using individual accounts. Likely laying groundwork for Steam Machines to exist in the living room for a family to access.
A similarly geared feature is Family Options, which adds parental controls to Steam (again, another step towards Steam Machines).