-12x^4 + x^3 + 10x - 4
To write in standard form means to order the terms in order of highest to lowest degree.
"Degree" means exponent. So in simpler words, you order the terms in order of descending exponent value. Ex: x^4 - x^3 + x^2...
Also, you write the terms with variables before the terms that are only a constant, which is why 10x comes before -4.