Whats the difference between “Attack-move” and right-clicking a location?
By default, if you right-click a location on the map, all selected units will “Move” to that location, ignoring any enemy units. Right-clicking on an enemy unit or building will order your units to destroy that target, and ignore any other enemies until the job is done. For more flexibility and responsiveness, you can use the “Attack” command on a location instead. Units ordered to attack a location will move towards that spot, and automatically attack any and all enemy units along the way.