Define the health topic, using a reference.
Describe the epidemiology and current prevalence in your target group and target setting (place, area, country) using reliable surveillance and / or peer-reviewed data.
Explain its evidence-based determinants for your target group (consider doing this within the Rainbow mode or other social determinants of health model).
A figure might be useful here, mapping the determinants of your health topic for your group in their setting, mapped to a recognised model.
Explain the evidence-based harms of the problem on your target group, to justify why an intervention is needed.
Explain what health promotion is (aims, perspectives, strategies), and why it is a good fit to your topic. Identify the most relevant WHO Charter for your topic.
A figure might be useful here, showing the action areas of the Ottawa Charter for Health Promotion
Critically discuss the needs assessment of your choice for your target group and setting. Ensure you use peer-reviewed evidence and / or surveillance data to support this.