In a health needs assessment, you identify health problems prevalent in your community. In other words, you look into any local health conditions which are associated with morbidity, mortality and disability. The local problems may include malaria, TB, HIV/AIDS, diarrhoea, or other conditions arising from the local context, such as goitre caused by lack of iodine in the diet.
Having identified the problems, you need to think about the extent to which local health conditions are a result of insufficient education. For example, are people lacking in knowledge about malaria, or HIV, or diarrhoea? Are they aware that some of their behaviours may be part of the problem?