You can use two possibilities to get to coordinates above:
First (easy way - drop 45 m) from the church in Ruda (N 49°51.834', E017°11.178').
Second (harder way - drop 270 m) from village Brevenec (N 49°51.493', E017°09.403') by yellow tourist mark.

On the top you have to calculate new coordinates of next point:
N 49°51.AB'
E017°10.CDC'

A = half of the total number of crosses arranged here
B = 4 * number of the cross with text "IESUS WIRT AN DAS CREUTZ..."
C = number of the cross with text "IESUS WIRD INS GRAB..." - 8
D = number of the cross used for B calculating - number of the cross with text "IESUS WIRD ENTBEÖSET MIT GALL..."

On that new place you will find group of some objects which one of them doesn't belong to the others.
From that point go in the direction EFE° for the distance G m and there, next the "twin", you will find the cache.
E = G/C/10
F = number of identical horizontal parts of that different object
G = 10 * number of the biggest cross

I wish you goog luck and lot of beautifull time spent on that extraordinary place.