AuraAlarm alerts you to buffs and debuffs by playing sounds or flashing the background a certain color. Also an icon of the buff is shown. It has two modes of operation: normal mode and light mode. Normal mode has more features.
To deal with this there are Sets, and you can change into a set through a slashcommand/macro (/auraalarm getset Default). For each set you can specify a target's name. This way you can switch into a Lich King set simply by targeting LK himself.
One of normal mode's features is collision handling. To deal with two or more alarms intersecting, the alarms' individual colors are alpha blended together. You can also prioritize alarms so that when two or more alarms intersect only the important alarm's color shows up. To set up priorities you use layers and the alarm's alpha value. By setting a layer 1 alarm red and fully opaque and a layer 2 alarm that is blue, you have caused the layer 1 alarm to cover up entirely the second layer alarm. The background is entirely red, no matter how many alarms are on layer 2 or deeper.
Normal mode's biggest difference is that it will catch every buff and debuff. Light mode may miss auras that never show up in the combat log, such as Lich King's necrotic plague. Also it doesn't have collision behavior, so if one alarm interrupts another, the behavior is undefined.
When you want alerted to a stackable buff, but don't care what stack it is, use 0 for the stack parameter. Also use 0 for non-stacking auras.
Note that when copying one alarm's properties, only these attributes are shared: color, mode, soundFile, soundPersist, soundRate, showIcon, and layer.
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