The images below show the back cover replacement straight out of China. You then place the device with its new cover on the charging pad for the wireless magic to happen. The charging pad itself has to be wired up, of course.
Wireless charging is a pretty convenient bonus feature, especially for smartphones with not so great battery life. The Galaxy S4 on the other hand has one of the best battery capacities of current high-end smartphones with a 2600mAh juicer. It ranks on top along with long-lasting devices like the HTC One and Apple iPhone 5.