Sample problems are an option that you will see on the requests of many new students. They'll be labeled like this:
Check to see if they want to work on the sample problem OR their own homework.
Explain that you can use the sample problem to show them how the app works or that they can switch to their own problem if they'd rather do that.
Say something like this:
"We can use this sample problem here to give you a sense of how the app works or we can use one of your own homework problems if you have something you need help with. Did you want to get started with this one?"
If they want to use their own problem, explain how to upload a picture.
Example Session Notes for Sample Problems: