Citing correctly means putting an in-text citation right after the end of a sentence that contains information that you added that came from someone else.

That's it - that simple, but also that necessary.

You'll have either:

a) directly quoted that information by putting double quote marks around the statement

b) or if it was a larger amount of information, inserted it into your text as a block quote

c) or paraphrased it (re-written it in your own words).

Regardless of which you did, you'll add that in-text citation. Depending on which citation style you use, it will be:

a) parentheses containing one or more author last names, and a page number and/or a date (year)

OR

b)  just a little superscript number. Some citation styles using superscripts require footnotes (little sentences at the page's bottom margin) or endnotes (the little notes are at the end of a book chapter). Other styles just have a bibliography at the end of the article.

In-text citations exist to give credit to the authors you got the information from, and must match up with the sources listed in your bibliography at the end of your paper. This is so that anyone can go see the exact sources you used, and go retrieve them for themselves.

Many researchers looking up literature on a topic 'mine' the references and works cited from articles their fellow researchers published, as you also will.