To find the cache you have to play a whereigo cartridge. The cartridge can be downloaded here (username and password is the same as you use on www.geocaching.com).
This whereigo can be played anywhere, however you will need to be within 30km of the listed coordinates to learn the location of the geocache. You need a diameter of approximately 80m of space for your play area. There is enough space to play at the listed coordinates. The physical cache is not far from the listed coordinates in the remains of a battle.