A sort of basic understanding of how to implement it would be to assume you have a points-based system for admission, which takes into account things like previous grades, standardized test scores, etc., and normally has a minimum threshold of n points for admission.
One way to think of affirmative action is that it says "people from this group, on average, will score k points lower not because of a lack of ability or intelligence, but because of a lack of opportunities earlier in life due to social inequalities", and then asks questions about whether a score that is within k points of n should be admitted.
The real implementations are more complicated, of course, but this is the basic idea. The main problem with it is that starting to apply remedies for inequality after someone has already lived through 18 years of it -- and 18 important, formative years at that -- is nowhere near enough.
Some things you just really want to believe.
Which is why the people actually helped by affirmative action tend to be middle class people from favored ethnic groups who had opportunities.
"Affirmative action" is a terribly divisive, blunt tool which creates more injustice than it remedies. The idea a poor white guy from a broken home in Appalachia is somehow starting out behind a middle class black girl with an intact family in Southern California is laughable.
Sure the most powerful people in the world are usually white men, but as you said that doesn't really mean much to the average poor rural white kid.
Also income is also highly correlated with race, so disadvantaged minorities would benefit disproportionately anyway.
I'm not sure what this typo should mean, but I do know it needs to become a central phrase in American culture.