I'm supposed to find a polynomial with specified Zeros. This is all the question told me:

Degree: 4
Zeros: -2, 0, 2, 4

I know how to do these problems when it's a degree of 3, but not 4.

When you do one for degree of 3, don't you just form 3 factors from the given 3 zeros?

Well, now you just have 4 of them
so
y = x(x+2)(x-2)(x-4)