A 5 to 10 minute film is something I always compare to a joke. You
want the set up, the story and the punch line. This works even
with drama, thriller, horror, etc. A good ending (the punch line)
is even more important in a short than in a feature.
Since the “one page, one minute” standard really only works for a
feature length script, I’m not sure that a page count for a five
minute movie would be very accurate. But Scoopicman’s breakdown
looks pretty good to me for 10 minutes.
My advice is to watch a lot of short films. Then rewatch five that
worked for you and five that didn’t. Study why.