Open. This opens the link to the Google Slides file where you used Plus AI to generate this presentation in a new tab. Note that if you edited or deleted the slides after generating them, you cannot restore them. This simply opens that file.
Reuse. This launches the presentation generator with the same prompt(s) and settings filled in, which you can then edit, just like when generating a brand new presentation. You can also click reuse to see what you prompt you used without proceeding to the "generate" step.