How to create Volume slider control ?

Hi, everyone. i'm very new to implementation of volume slider control options, i.e., increasing and decreasing volume level in the game. I saw in many games there is a control(slider) to reduce the music and sound effects. how can i create a volume slider control in TGB.... help Me.

I know that, there's a control in GUI Editor(GuiSliderCtrl) but i don't know how to use this into the game.