Discussion or Debate for adult students

Describe in detail how I would use in a lesson. Use step by step bullet points and how I would conduct the activity.

I am really stuck on what to discuss to even get started. I understand I need to introduce the lesson by pre-teaching (photos, video etc.)

Then to elicit keywords and put them on the board. Putting students into certain groups to discuss the topic.
Please can someone help me structure this lesson and guide me into a discussion. I need to mention what level the learners are. Thanks. Juliet