Repeater
Here are all the settings that determine how the duplicate layers are positioned and oriented.
X, Y and Z Offset
Determines how much the X, Y and Z position is increased (or decreased) for each instance.
X, Y and Z Rotate
Determines how much the X, Y and Z rotation is increased (or decreased) for each instance. Notice that this rotation is around the Main Null (created when you hit "Repeat").
Scale
Determines how much the scale increased (or decreased) for each instance.
Opacity
Determines how much the opacity increased (or decreased) for each instance.
X, Y and Z Offset Random
This control allows for randomly spacing out the instances on the X, Y and Z axis. Useful when you want to just spread out the layers randomly in space