Q: how do I play Keynote on apple tv

I'm using Keynote for the first time (first time to use any slide presentation, actually) and I'm trying to get it on my TV with my Apple TV.  When I click on Computer through  Apple TV it directs me to open sharing in iTunes  which I have done, but how do I play Keynote through iTunes?  any other ways to get it on my TV?  What about Air Play (I don't even know what that is, I just found it mentioned when looking for answers to my problem...)?  Mom's 90th birthday party is this Sunday and I'd love to show the slide presentation on my TV, but not sure how.  Any suggestions?