To find rational answers, factor the constant term (32) and divide each of these numbers by the factors of the coefficient of the iinitial term (1).
The factors of 32 are +1, -1, +2, -2, +4, -4, +8, -8. +16. -16. +32, and -32.
Try these, one at a time, until you find one that makes the expresssion zero.
If you try +1, the expression becomes zero; this tells you that one of the answers is +1, and one of the factors of the expression is (x - 1).
Now, there are a couple of things that you can do.
You can divide the original expression by (x - 1) to give you a smaller expression:
x4 - 2x3 -4x2 - 8x - 32
Again, factor the constant term (32) and divide each of these numbers by the facotrs of the coefficient of the initial term (1).
And again, these factor are +1, -1, +2, -2, +4, -4, +8, -8. +16. -16. +32, and -32.
Try these, one at a time, until you find one that makes the expression zero.
This will give you a second solution ... create the factor .... divide, and continue this process until you can no longer get another solution.