Explanation:
You basically have to divide your number from a prime factor until your result is 1
For example
12
you divide it from the lowest prime number possible, for in this case, 2
12/2 = 6 and you can set aside 2 for now
You do the same thing and you divide it by 2
6/2 = 3 and set aside 2
Now 3 isn't divisible by 2 so you'll find another number, for in this case 3
3/3 = 1
your set side numbers are now 2,2,3
so you'll find out 12 = 2x2x3 as a product of it's prime factors
how ever you cant divide it by 4 or 6 since they aren't prime factors as they are divisible by other numbers