If you want to shuffle slides in PowerPoint randomly, you will have to use VBA macros. Learn how to randomize slides in PowerPoint.

You can combine multiple PowerPoint Presentations using Reuse Slides, VBA code, Cop-Paste. The 1st preserves formatting while the 2nd can merge any number of files.

You can change the size of a slide in your PowerPoint presentation through the "Design" menu on the Windows PC, Apple MacOS, and web-based apps.