Answer

You can easily access the kit documentation for all of the EFM8 STKs using the main launch screen of Simplicity Studio.  From this screen, click the Kit Documentation tile. 

This will cause the Kit Documentation dialog box to pop up.  In the filter field, type EFM8.  A list of available EFM8 kits will appear, with options to view kit documentation including assembly drawings, BOMs, schematics, User Guides, and Quick Start Guides.

Double-click on the desired documentation to display.