This YouTube video is great as a refresher on Boolean searching techniques.
To begin your research, identify the major keywords that will help you find relevant information. Then, think of alternative search terms or synonyms: e.g. physical activity may also be referred to as physical exercise, and diet may also be referred to as nutrition.
If you cannot think of any other terms, read a few articles on Summon, or read items on your reading list, and look at the keywords used in these. Be creative and think around your topic.
The video below will give you some guidance on picking out keywords from your assignment question, and on the importance of using synonyms.