If a classmate comes to you with questions about an assignment or paper, talking about ideas can be a very helpful practice for everyone involved (you might come to new conclusions as you share your thoughts with your classmate!). If your classmate is still confused about the assignment or essay, you can always suggest they visit their professor during office hours or to make an appointment at the Writing Center. 

Many instructors will have clear expectations about what will and will not be group work in a course.  If you or a classmate are caught working together on individual work, it can be considered a violation of the Academic Integrity Policy.