Uploading Powerpoint slideshow with narration

I would like to add a powerpoint slide presentation with narration to our class wiki page. I have uploaded a saved powerpoint file by clicking on attach file. It uploads with a icon that is a page with a question mark in it. From my mac, proceed to open it, and it asks me to choose a program to open it. I have to choose powerpoint to open it. The slides show up in the program and I have to choose -->view slide show, to see the show. The narration does not come up. Instead it says that narration (file) is not found.
My Question is...
How do I upload the slide show on the wiki and make it easy for people to open and access it. As my students are young... 8 -9 years old, and we spent many hours learning powerpoint and recording narration, I would like to stick with this program.

Thanks.