Universal Serial Bus (USB) is a serial bus standard designed to allow peripherals to be connected to a computer by one standard socket. USB devices can be connected and disconnected from a computer without the need for restarting it. The vast majority of USB devices draw power from the USB port and require no external power supply. USB is a standard designed to replace serial and parallel ports and there are many different USB devices today, keyboards, joysticks, cameras and printers to name a few.
The physical installation of a USB wireless card is very user friendly, simply plug in your device as pictured. The only point that you must bear in mind is that there is a "right way up", the USB connector has a flat blade on the female connector that is offset to the top and matches a corresponding slot in the male connector. So if it doesnt go in one way just turn it upside down and try again. The male connector should slide into the USB port with very slight resistance. Once connected correctly the computer should detect your new hardware and you can move onto the installing drivers section relevant to your computers operating system.