UX moderation skills on a task list

I am user testing a task list on the homepage. If the participant clicks on the task list, each task has many screens. I am only really interested in the person interacting with the task list and starting the process and not all the interactions after. What is the best technique to keep the participant from going down this rabbit hole?

Do I allow the participant to click on the task but only show the first screen of the sequence thus successfully showing they have interacted with the task list but then stop the participant from going further and bring them back to the homepage/task list for the next scenario? If so, what is the best way to word this to the participant?