Changing a Slide Design

I am currently tasked with editing an Articulate project that has a custom slide design with link button incorporated in it. However, I cannot figure out how to access the design itself to update the links the buttons go to. I was not provided any design file (if there is such a thing) for this.

Am I lost without a design file or is there a way to access these buttons that I am not aware of? Please note these button are not part of the player.