Open the presentation you want to add the slides to.
Step2
Go to the View menu and select Slide Sorter.
Step3
Position the cursor to the right of the slide you want the new slides to follow and click; a vertical line will appear where you want to insert the slides.
Step4
Go to the Insert menu (Mac OS) and select Slides from Files; all of the slides from the other presentation are placed into this one.
Step5
Go to the Insert menu (Windows) and select Slides from Files.
Step6
Navigate to the presentation that contains the slides you want to use.
Step7
Select the slide you want to insert and click Insert, or select Insert All to insert the entire presentation.
Tips & Warnings
The exported slides will use the Slide Master and color scheme of the presentation they were exported to.
In the Mac OS, you can export specific slides, instead of the entire presentation, by opening both presentations and going to Slide Sorter view in both files. Select the slide you want to export (hold down the Shift key to copy more than one slide), then hold down the Option key and drag one of the slides into the other presentation. Let go of the Option key and mouse button when you see a vertical line in the position where you want to insert the slides.