A set-up shot is a shot of somebody who you are interviewing.
You need to shoot a set up shot of everyone you interview (apart from vox pops).
If you have time, it’s always better to get an action sequence — a series of shots of them doing something related to the story.
If you don’t have time to shoot a full action sequence then shoot a simple single shot, maybe of them walking through the frame either with or without the reporter next to them.
Here’s a simple walking shot set-up. You could do the same shot with the reporter walking along with the contributor and talking to them.