No need to be embarrassed; this is exactly the place to ask those sorts of questions.
From left to right, the buttons are:
-dot with three curved lines above: turns wifi on and off
-light bulb: keeps LCD screen on at all times (no time out)
-bluetooth: turns the bluetooth on and off
-Sun (half white, half black): toggles between different brightness levels
-Lock: puts the eDGe into sleep mode (wait ~2 seconds after the screen goes dark before shutting the eDGe)
In general, if the green bar below the button is lit, that feature is active. If it is white, the feature is inactive.
hope that helps!