Add same trigger to every slide

What are the trigger supposed to do? 
Perhaps you can put the trigger on the slidemaster?  (view - slidemaster) 

Hi, thanks for your answer. I will try this way.

Hello Antonio,

You could also set up the triggers, then duplicate the slide instead of inserting a new one. 

Hi, can I piggy back on this? I would like to add a trigger to " jump to next slide when media completes" to 90 slides. Is this possible to do with out doing each individually?

Hey Abbie. The unfortunate thing about "when media completes" is that it needs an explicit object to fire. If you create a trigger using When: Media completes you see that the Object: has to have a file to fire the trigger. Since each page will have a different media file you can't, AFAIK, make a universal edit like this. 

Would something on your pages prevent you from using the "When timeline ends?" If not then you could, as Jacob suggested, use a master page to add the trigger. Remember, it will only work on pages that use that master's layout. If you have more than one layout you're using for your pages you'll have to add the trigger to the other master pages too.