This is a Multi-cache, you have to get the information at the first waypoint to be able to get to the final!
Leave your car at the coordinates. Take the way left which goes slightly up and after some 100m enter the forest on your right (trailhead - hidden path)
From the final go down to the creek - have a view at the building (see gallery) - you can return to your car following the creek on the "autopedestre" path.