It’s pretty easy. In the Apps tab make a Windows app instead of an iOS app. Use whatever image you want for all of the image assets, you don’t even have to resize them (App Builder will resize them for you).
Some of the fields on the General tab can be a bit confusing, but since you aren’t submitting this to the store you can put in fake info. For publisher display name put in anything you want. For publisher ID use CN=testing. For main package identity name use something like com.yourcomanyname.yourappname.
Make sure you select the “Enable preview” checkbox!
Sandee, Neil is alluding to the fact that there are no viewers for DPS 2015 unless you create one yourself.
Without an Apple Developer account iOS is out of the question but you can build and install a Windows 8.1/10 app and use that since it doesn't require any certificates.
OK, let's pretend I am a ten year old trying to do this for the first time.
I open InDesign on Windows 10.
I create an MSO with several images.
I select the MSO.
I set it to Slideshow in the Overlays panel.
Now, what do I do to build a Windows app?
Where is the App tab? The App Builder? The General Tab?
I don't have any of those things.
And I don't see them if I choose File > Export > DPS Article