The Horizontal Alignment band supports multiple ways to adjust the relative position of two or more selected objects.
Similar to most page layout software, options include aligning figures to the left or right edges, centering them, or evenly distributing their centers from left to right.
Keyboard accelerators are assigned for all of these commands as that can provide a faster workflow in aligning many objects. Drag-To Guides are useful in aligning objects also.
Left
Cmd-L Align two or more selected objects to the leftmost edge of the selection.
Right
Cmd-R Align two or more selected objects to the rightmost edge of the selection.
Center
Cmd-. Align the horizontal centers of all selected objects
Spacing
When three or more objects are selected, this function will space their centers at even intervals. The more figures that are selected, the smaller the spacing between each image will be. Note that the command distributes the centers evenly, as opposed to using the edges of the objects.