A precis is a summary--a short, descriptive paragraph or two in which you describe the argument and structure of a piece of writing.  This summary should not judge or evaluate the piece of writing.  Rather, the piece should breifly describe the main idea of the work.  How does the author make his or her case?  Is there an identifiable structure or form?  You should state the author and title of a work, then briefly outline the main idea.  Next, explain in a paragraph or two the major events and the structure by which the author conveys the main idea.
    Since you have just read Hawthorne's "Young Goodman Brown," write a precis that sums up the main idea.  Do not feel the need to quote or give examples--simply summarize.