How to Use Multipe Slide Masters in PowerPoint
The slide master and its layouts are different depending on which theme you have selected. But if you like, you can use more than one theme, thereby giving you access to multiple slide masters and their layouts.
An additional slide master appears along with its slide layouts.
The slide master and layouts have placeholders but no formatting, so you’ll have to customize them yourself.
If you want an additional slide master with more complicated layouts and formatting, add another slide master from a theme.
The slide layouts will be grouped into sections corresponding to the slide master. You may have to scroll to find the one you’re looking for.