To perform searches, you will need keywords.
Let's practice brainstorming keywords by looking at a sample topic...
Animals in Ancient Egypt
What are our major concepts?
1. Ancient Egypt
We can use these as keywords, but there might be other words that work better for our topic. Let's think about synonyms and related ideas for our major concepts:
1. Anicent Egypt - Egyptian
2. Animals - Cats, Pets, Domestication, Dogs, Religion
Next, combine any one of the keywords from each group using AND.
1. Ancient Egypt AND pets
2. Ancient Egypt AND animals
3. Egypt AND cats
4. Egypt AND cats AND religion
Different combinations of search terms will give you very different results, so you may want to try several different search strategies to see which gives you the best results.