Okay, so your denominator is the number at the bottom. You want your denominator to be 24.
2 over 4 = X over 24.
So first you need to know that 4 multiplied by 6 is 24. So then you need to multiply your numerator, the top number by 6 as well.
2 multiplied by 6 = 12.
12/24 is your answer