1. How to use StackInterleave
Open this file (StackInterleave.PPTM)
The files you want to Stack or Interleave should be in one folder together. No other PPT files should be in that folder.
Open any one of the files and make it the active presentation.
Press Alt+F8, choose “Macros in: StackInterleave.PPTM”, click either Stack or Interleave then click RUN
Your files will be Stacked or Interleaved into a file called OUTPUT.PPTX in the same folder as the original files

2. Stack? Interleave?
Suppose you start with three files, A, B, and C, each with 3 slides:
If you choose to STACK them, you’ll end up with a new OUTPUT.PPTX presentation containing slides 1-3 from A, then 1-3 from B, then 1-3 from C
If you choose to STACK them, you’ll end up with a new OUTPUT.PPTX presentation containing slide 1 from A, 1 from B, 1 from C then 2 from A, 2 from B, 2 from C and so on.

3. Tips/Notes
The presentation files you want to Stack or Interleave must be together in the same folder
ONLY those files should be in that folder
The files should each have the same number of slides
The files will be Stacked or Interleaved in the order in which they were created (later we may add the ability to sort the names, but not for now)
The result will be saved to OUTPUT.PPTX, in the same folder as the slides being Stacked/Interleaved.
Any previous copy of OUTPUT.PPTX will be deleted