To avoid plagiarizing:
Paraphrase: put the ideas from the text COMPLETELY into your own words. Even when paraphrasing you must still use in-text citations as well as including it in the works cited section.
Use quotation marks around text that has been taken directly from the original source.
Cite every source of information you use in your paper unless it is common knowledge (i.e. the sky is blue) or the results of your own research.
Every discipline has their own citation style, however, every person/professor is different and they may have a preference for a different citation style, or prefer that you use an older format for citations. The books below are examples of the texts that can assist you with properly citing your sources.