The download button opens the iTunes App Store, where you
may continue the download process. You must have iTunes installed with an
active iTunes account in order to download and install the software. This
download may not be available in some countries.
From Albert Pascual:
This app provides information to hikes that other hikes have reported, PCT makers, water spots, shops, check points, other hikers on the trail, transportation, snow issues as well as trail magic caches. All this information is contributed by hikers with this app, so please, report all that information for other hikers behind you. All the reported information is tag by location and time. The app works uses your location to enter the information. This application may continue to use GPS in the background, which can dramatically decrease battery life.