The design uses a circuit board that I found in one of the local markets being made and sold by a self educated entrepreneur. The board is available on ebay
The circuit board has connections for DC9-12V input, battery terminals indicator LEDs and power LEDs. Follow the picture to connect the board with battery, indicator LEDs and switch.
House them in a case of your choice and you have a fantastic LED lantern that turns on automatically when AC power goes or sun goes down. You can get about 10hrs of light time with this setup.