With your Blender project open, you select one of the 3D items, such as that "150m12.5_dig" showing in the "Collection" in the right-hand pane. You then select (if it doesn't default to it) the "Object Properties", which is that little orange solid box inside the brackets there between the 3D window, and the lower right-hand pane. That will have the X, Y and Z Location, as well as the X, Y and Z Rotation. Those numbers can be used directly in the Placement node. The problem comes in with the differences between the S3D (maybe Pack3D also) obj "orientation". S3D like to export the 3D obj "vertically", like an airplane or ship on its tail, whereas Blender likes things horizontally, on its wheels. It's been too long since I worked with something exported with Pack3D, so I do not remember its orientation. Anyway, suffice to say, you might have to reverse the Y and Z Locations and/or Rotations, and possibly have to convert from a negative number to a positive for one of the Location settings. Besides all that "looking things up manually", experimenting with the Placement build in the game is almost always necessary. So view it in-game before going much beyond a few of the obj Object Properties, or you might find you end up with a jumbled mess, like I had for a good while. Sometimes also, a person has a tendency to over-think things though, and combined with covid brain, it can get ugly...
