The shield has the GPS sensor, an onboard microSD card slot (for data logging / other general use), and a coin cell battery for up to 7 years backup. The onboard u.FL connector allows an external active antenna to be used in place of the internal patch antenna.

GPS can be a little overwhelming for beginners, but like most Adafruit products, there is an excellent tutorial going through the basics linked below.

Please Note: Minor soldering is required to attach the included breakaway headers.