My sense, as odd as it might seem to us, is that they put these shows together to the final cut very quickly in a few days on the fly. It must just quickly fall into place for them typically.
Yes, but they are highly skilled at this. You are already selected, so they know that you can do it. They will probably coach you and go over the plan with you and you will rehearse. It looks to me like they give the women who appear on the show a hair-do and facial makeup. I don't know what they do for guys. Get a nice suit or sport jacket. Wear a tie and a neat looking shirt. But my advice is to be thinking of what you will say in advance. My wife was a speech and debate coach. She was good at it. She told me how to rehearse what I would say in my oral exams, etc. Prepare your words in advance so you won't have to stumble for words.
Following is my guess as to what will happen: You will all be seated together on production stools in a line on the stage. There will be cameras and lights and an audience staring you in the face. Prepare yourself so you won't be dazzled. Oprah will be seated to your left. She will explain to the audience what's going on in several minutes. She is amazingly effective. She knows the pain of abuse and so she will be sensitive. She will probably give each of you 1 or 2 minutes to introduce yourselves. This will include your name and where you are from and what you do. Don't be embarrassed if you are unemployed. That will be part of your "story". Then Oprah will talk several more minutes to sum up and prepare for the next round of your statements. Each of you will be given several minutes to tell your story of abuse. Be prepared to tell your story in a short period of time like that. You cannot hem and haw. You must practice beforehand to be effective. Write out your statements and memorize them. Say your story to a friend. Be prepared and it will help you not be stunned (remember the deer caught in the headlights of a car?).
Oprah will ask each person several questions relating to your story. She will be direct but she will be very sensitive to not embarrassing you. Give direct answers if you can. She will want to know the nature of the abuse then and how it affects your life now. They may ask about your perp. Be prepared to describe the perp in a few words without giving any names. What is the perp doing now? Etc. etc. Then they will have a commercial break.
Then they will come back and she will re-summarize what's going on. Then they will have more interview-type questions for you. They may ask to show some pictures of where you are from (your childhood home) or something. Or maybe they will show a picture of you as a child. Remember it's a visual medium. The time will go very, very fast.