This app has two groups of location coordinates that can be entered by the user.
The upper x, y & z coordinates are used to calculate the lower x, y & z coordinates.
Or, the lower x, y & z coordinates are used to calculate the upper x, y & z coordinates.
The x & z coordinates, for both upper & lower can be changed to minus numbers, with the use of the, plus/minus buttons.
When you have your upper & lower coordinates worked out, they can then be saved, with the save button, as a new location, & also renamed by the user to something like my base or my farm or anything the user can dream.
Your saved coordinates, can then be viewed sometime in the future, by you the user, via the, view saved locations button.
end.