Menu driven PowerPoint presentations

[Sigurd]

I am hoping to setup a series of short PowerPoint presentations in our local historical Priory which visitors can select via a numeric key pad. Briefly it system comprises a laptop running Powerpoint in a cabinet, an external screen , and an external keypad. An index either on screen or written next to the screen details the presentations each with a number and the visitor selects the one wanted by keying in the number via the external keypad. For management simplicity, when the laptop is switched on it will automatically start PowerPoint and run the Home Screen of the various presentations.
No problems setting up the mechanics or the presentations, but how do I

1. Ensure that PowerPoint automatically loads the Home Screen presentation on switch on (I know how to autostart an app on switch on, but how do I load a specific presentation)
2. Create a Home Screen which waits for a numeric input to start a selected presentation running
3. Sets the appropriate presentation running in response to the number selected
4. Ensure that PP goes back to display the "Home Screen" waiting for the next selection

Thanks.