Download the .zip archive and use a tool such as 7-zip for Windows or The Unarchiverfor MacOSX to extract its contents.
Move the extracted folder "Scope Faces Megapack 2016" to:
\Documents\Sports Interactive\Football Manager 2016\graphics\
Create the folder "graphics" if it doesn't exist.
Open Football Manager 2016 and go to Preferences > Interface.
Click the "Clear Cache" button.
Enable "Reload skin when confirming changes in Preferences".
Click the "Reload Skin" button.
There should be a box that pops up saying 'loading image data for the new skin'. Once this is done your graphics should be working within the game.