Every in-text citation must correspond with a full citation on the Works Cited page, and vice versa. You can't include a source in your references list if you don't also cite it in your paper.
Place at the end of a sentence, before the ending punctuation mark.
If preferred, include the author or title of the cited work in the signal phrase by which you introduce the content. Then, the parentheses only contains the page number.
For short quotations, which consist of four typed lines or fewer of prose and three lines of verse, add quotation marks around the words and incorporate the quote into your own text. Include the author and page number in the parenthetical citation.
For longer quotations of more than 4 typed lines of text or more than 3 lines of poetic verse, format the quote in its own paragraph, with the entire section indented 1/2". Do not use quotation marks around it, and include the standard citation information at the end.
For example, if you wished to quote a longer section from Alice's Adventures in Wonderland, that would be formatted as a block quote:
When the rabbit actually took a watch out of its waistcoat pocket, and looked at it and then hurried on, Alice started to her feet, for it flashed across her mind that she had never before seen a rabbit with either a waistcoat pocket or a watch to take out of it, and burning with curiosity, she ran across the field after it, and was just in time to see it pop down a large rabbit-hole under the hedge. (Carroll 10)
When borrowing more than one time from the same source in a single paragraph, there are multiple options for citing. You can give a parenthetical citation at the end of each sentence. If the reader can easily determine that the same source is being cited, then use of the page number alone is sufficient.
Another option would be using a single parenthetical citation after the last borrowed source.
Keep in mind that you may need to reintroduce a source, either in prose or in parenthetical citation, for clarity, such as after citing a different source or including your own ideas.