Hmmm ok let's say you have 3 triggers, and you want number 1 to activate first but you don't want 2 or 3.
Make the #1 as you want. But in its On Activation field put, after the code you wanted to put, "trig2=true".
Now create the trigger #2, put its condition line. For example let's say you want the player to be at a certain place, so make the trigger over the area, group it with the player and now, in the condition line of the trigger you'll see "this", then add AND trig2, so it will be "this AND trig2"
In the On Activation line of the trigger put whatever you want, for example hint "Hellooo" and then add at the final "trig3=true": hint "helloooo"; trig3=true.
Now create the next trigger, put the condition line you want and add "AND trig3". You get the idea?