Welcome to the forums..There's no official guide so far, but hovering your mouse pointer over most things will pop up a brief description of the function if Tool Tips is enabled in the settings, which it is by default..EVGA Precision's available features will greatly depend on what series of card you have, if you have an EVGA card or not, and the version of EVGA Precision you have..You should list all your system hardware and OS.
 
You can go to YouTube and search "EVGA Precision" and you'll find many overclocking guides/tutorials there..You can automatically or manually (in Custom Settings) Optimize your games using GeForce Experience if they are supported games..You can Revert GeForce Experience optimization should it not work out well..Many people have a dim view of GeForce Experience because it has been known to cause problems, others not..You can find optimization guides at GeForce.com for some games and hardware..Games also have some kind of performance preference settings in their menus...Game developer websites/forums might also offer optimization info..NVIDIA GeForce Forums is also another source for good stuff.
 
Be sure to have the latest NVIDIA Driver and your games are updated as needed..If you have any other questions or need help, just holler.