tinkerkit accelerometer

hi. i am trying to make a motorcycle alarm using Arduino. i need a 3 axis accelerometer to detect movements with the bike. the tinkerkit accelerometer is a 3 axis accelerometer but it says to enable it i need to solder a header to the hole that says z. first of all i do not know how to do that and also how would i then connect that to the shield, and this might sound like a stupid question but what is a header. I am new to electronics. Any help would be great. Thanks

Your question is about this: http://www.tinkerkit.com/accelerometer/

It says: "You can get data about the third axis (referred to as Z) by soldering a header to the thru-hole labeled ā€œZā€"

A plug is a connector, like a mains plug or an audio plug. A connector can be anything small or big. A header is a few metal pins, sometimes a double row of pins. http://en.wikipedia.org/wiki/Pin_header

Look at the labels on the backside near the connectors. The connectors for the tinkerkit are "+", "X", "-" and "+", "Y", "-". The unused header (the holes) are "X", "-", "Z", "+", "Y".

To get the Z-axis to the Arduino. You could solder a row a metal pins or perhaps only the 'Z'. And get the Z-axis somehow to the Arduino.