To some folks citation feels like an elaborate, torturous form of hazing.
Actually, hazing isn't too far off base, since each field of study has its own citation preferences, and learning to cite "the right way" is part of what it takes to become a member of the group.
Psychology uses APA (the American Psychology Association).
Literature and the various fields of language study rely, by and large, on MLA (Modern Languages Association).
History mostly sticks with Chicago Style - plus a variation known as the Turabian method (for the late, great Kate Turabian, a U. of Chicago secretary who spent nearly 30 years making sure that PhD students cited correctly).
In fact there are no less than 20 citation systems in regular use. There is no hope of a unified system in your lifetime or mine.
Not only have the various citation formats become part of each field's "identity" - they can be serious money makers. Which is why you won't get full access to new APA citation guidelines just by googling.
Since you might as well make peace with the issue, here are THREE QUICK WAYS to get ahead on citation.
1. One of the big three systems (MLA, APA, or Chicago) will usually work for most non-science courses. And - ta da! The Purdue University Online Writing Lab, among others, offers a reliable, easy to follow guide on using each one.
2. At the start of a new course, check the syllabus to see if you'll be writing papers that require proper citation. Find out what citation format will be expected, then bookmark a resource on it so you're prepared before you start to write.
3. Gather the relevant info on every source you use (author name, title, date, etc.) right when you use it. And always note the page numbers for specific ideas or data or quotes.
Never, ever say to yourself - "I can go back for the details later if I decide to use this stuff." That can only lead down a slippery slope to a place where it's 2 am and you're all out of coffee and the paper is due tomorrow and so you decide, what the hell, you'll just throw in a few facts and quotes you found during your research that you can't find the citations for…
And that's plagiarism. Which will lead to far worse headaches than having to learn where to put the commas and parentheses in your list of references.