You decide where the clock hands are by knowing what each hand does. The small hand represents the hour while the big hand represents minutes. For the time 2:30 look for the numbers 2 and 3 the small hand should be in the middle and the big hand should be on the 6 which represents 30, keep in mind that the minutes go by 5 for example each whole number on the clock adds on by 5 the five times table would be helpful for this. For 2:50 the small hand should be closer to 3 but not on 3 and the big hand also known as minutes hand should be on 10.
Hope This Helps ;)