A clock has the numbers 1 to 12 spaced evenly around its face. It has two hands that point at those numbers:
Watch the long hand to read the minutes:
Each number the long hand passes is 5 minutes — so going all the way round the 12 numbers makes 60 minutes, which is one whole hour.
Here the short hand points to the 3 and the long hand points to the 12, so the time is 3 o'clock.