Edit Brush Dialog Box - Offset Tab
These options let you alter the distance between the original line and objects in the brush.
Direction from line
Select from the drop-down list. You have options for: on the line; to one side; alternately either side; or randomly arranged either side.
Distance
Controls the distance from the original line to the first brush object. Dimmed if On line selected. The distance of the other objects is controlled by the Adding and Random controls.
Random
Gives a random distance from the line. The slider limits the distance; for example, 50-200% limits the distance to between 50% to 200% of the original value.
Randomize
Generate a new random set of distances. If you prefer the previous values, click Undo.