The configuration menu can be accessed from within Media Browser using the wrench (or spanner) icon.
Some themes will show the wrench button on the Enhanced Home Screen.
For example, on default and diamond themes with EHS enabled, like this:
Or when using the Harmony theme on the EHS:
which is followed by 
Other themes have the configuration menu hidden. In these cases you most often have to navigate to either the top or the bottom of your screen using the up and down buttons on your remote control.
As soon as you are at the top or bottom item press up or down once menu to show a hidden menu where you can find the configuration menu.
For example, in Vanilla you need can find the hidden configuration menu button at the bottom:
If you use Chocolate the hidden configuration menu button is at the top:
Please note:
There also is a “Media Browser Configuration Wizard” (configurator for short). The “Configuration menu” and the “Media Browser Configuration Wizard” are not the same.
The Configurator is used for setting up your Media Collections, install Plugins and such.
You can find the Media Browser Configuration Wizard in the Windows Start Menu under:
Start > All Programs > Media Browser > Media Browser Configuration Wizard