Welcome to the forums, user452

The Pocket eDGe cannot be charged by USB. The mini-usb plug is for connecting it to your PC/Mac with the included cable in order to transfer files directly. The "Charger" is the AC adapter supplied with your eDGe. It plugs into the AC jack located between the power switch and hinge below the eInk side.

To turn off the LCD screen, add the Power Control widget to your home screen (press the Menu button, then "Add" then "Widgets" then "Power Control"). Tap the rightmost icon on the widget to turn off the LCD.

Hope this helps