Importing a Slide or Master Slide
You can import slides and master slides from other Keynote documents.
To import a slide or master slide:
Open the Keynote source document (the one with the slide you want to import), and
the current Keynote document (the one you want to import the slide into).
Do one of the following:
To import a slide, drag it from the slide navigator of the source document to the slide
navigator of the current document. The slide and its master are added to the current
document. (The master is the last slide in the master slide navigator.)
To import a master slide, drag it from the master slide navigator to the master slide
navigator of the current document.