Align
Moves every selected layer to line up on one edge or center:Distribute
Spaces three or more layers so a given edge or center is evenly stepped between the first and last layer:Distribute spacing
Instead of evenly spacing an edge or center, these two buttons equalize the empty gap between adjacent layers:The spacing amount field only takes effect when Align to is set to Key Layer. It’s the exact pixel gap used between the key layer and every other layer, cascading outward in both directions. For every other Align to target, gaps are calculated automatically to fill the available space evenly, and the field is ignored.