Identify the author's last name. If there is only one author, this is simple: just list the author's last name. If there are two or three authors, list all last names, separating the first and second with a comma and joining the third to the second with the word "and." If there are more than three authors, you can list all last names or simply supply the first one and follow it with "et al."
Identify the page number you are working or quoting from. Place it next to the author's name with a single space between them. Do not include a comma.
Place this information between parentheses and put it in the proper place in the sentence. The most common place it appears is at the end of a sentence. Always place punctuation after the citation regardless of whether you place it in the middle or at the end of a sentence.