Citation tells your reader that you got an idea from someone else. It consists of a little note in the text of your paper that lets your reader know, and then a much longer note at the end of your paper that tells your reader where to find the original idea.
Citation is tedious, boring and sometimes difficult. You still have to do it. Start collecting the information for your citations as soon as you start reading. Don't leave it to the end.
Most databases now help with citation. Look for a button or a link that says citation. Databases frequently make mistakes, so you have to check them. Check whether your instructor wants MLA 2003 or MLA 2007.