Having white skin confers certain advantages in this society. "White privilege" doesn't mean all white people live "lives of privilege," which has its own meaning (a life with few/no financial worries), nor does it mean that in every circumstance, any white person will have a better outcome than any black or brown person. It means there are certain advantages that having white skin provides that can't be changed by other circumstances like wealth or education or prestigious job. All of the things in that list provide their own advantages potentially, but entirely separate from having white skin.
Having white skin on average confers better outcomes. Being male on average confers better outcomes. Being straight (or assumed straight, which is why some gay people aren't openly gay) on average confers better outcomes. All of these are forms of privilege. In this society, if you have any of those things, you have a born-in privilege. That doesn't mean you're guaranteed to be successful (however you define "success") or that someone without them is guaranteed to be unsuccessful.
A lot of the advantage you gain from these things are invisible if you have them. It seems like you're just taken at face value, no more, no less. That's the benefit. People of color, women, LGBT+ people often aren't just taken at face value, left blank until they fill the blanks in themselves. They come loaded with cultural preconceptions right from the start that the average white person doesn't. That can have trivial consequences (like an awkward social exchange) or huge ones (like subconsciously being less favored for a job or housing opportunity, or being taken for threatening when you're just jogging), but these consequences are consistent and unending throughout life. Simply not having those is a massive advantage.
