Let students know that this will not be a permanent activity in your classroom because you want students to get to know each other. Students move one computer to the right or left and respond within the author's document. Every five minutes or so, students will keep moving in the same direction. Advise students to refrain from reading all of the comments that previous revisers wrote. This will help eliminate repetition and will save time.
Students can respond at the top of the document or within the paper.
I often spend an entire class period doing this exercise. Students more comments this way. If you prefer, have students add their name and email at the end of their comments. Then, students can communicate outside of class about their papers. Students send their papers to each other through email by either copying and pasting into the message or by sending it as an attachment.