I second davidcb's comments. If at all possible get some assistance from someone acquainted with electronics safety and assembly. In the end you won't be sorry you did. Your questions show that you perhaps have a little less knowledge than you should have to do what you intend to do.
Please don't take that as an insult. We only wish you to have a successful experience with your build.
Edit: The fan will have either two or three wires coming from it. Only two of them are necessary to run it. They will normally be black and red. The wires coming from the AC adapter will normally be both black but one will have a white stripe on it. The red fan wire normally goes to the black adapter wire with the white stripe. The black fan wire normally goes to the black adapter wire. Note that I seem to overuse the word "normally"? That's because you always gotta double check everything to make certain you don't have something non-standard. That's where familiarity with and a reasonable working knowledge of electronics comes into play.
Good luck and seek assistance from someone familiar with electronics or at the very, very least proceed with extreme caution and ask for help here.
Edit #2: Dang I wish the forum had spell check!!!!!!