You'll need access to students' PowerPoint presentations for the middle slides in your show. Be sure they're saved to the network, a single computer, a commonly accessible folder, or individual CDs. Then:

• In presentation you've begun to create, click between slides 1 and 2.
• Click Insert>Slides from Files, click browse, and locate the first student's PowerPoint presentation. You'll see all the slides in the student's presentation.
• Click one or more slides -- as many as you want to insert into your show. (Click "Keep source formatting" to ensure that slides retain their original background, fonts, and so on).
• Click Insert.
  
• Click Close.
• Repeat the steps above for each student presentation.
• Save your work!

Next: Let the show begin!