The short hand on the clock tells which hour it is. For example, if it's pointing at 7, then that means it's 7am/pm.
The long hand tells which minute it is. The numbers and space between the numbers on a clock mean five minutes, so if it's pointing at 1, it means (going with our 7am/pm example) it's 7:05. If it's pointing at 2, then another five minutes have passed (7:10) and so on until you reach the 12 again, which means that a new hour has started.
