Hi, I would like to ask what is special about the sound files that are classified as 3d and no3d. Does it mean that the sound will only play in one room?
3d means that the volume will decrease the further away you are from the origin/entity. No 3d means that it will be the same volume everywhere within the sound radius.
OK, and one more question to boot: what do I need to press/activate in the editor to show exactly how the lighting will look in-game?
You turn off the global lights, there are two buttons for it at the bottom of the screen. You'll notice if it is correct as the level gets A LOT darker.