There are several approaches to brainstorming, but the primary goal when brainstorming is to generate lots of alternative issues, perspectives and aspects of a topic without censoring them or worrying about their organization.
For any theme and/or issue that you consider, note as many aspects or ideas as come to mind. At this point, don’t worry about whether they are suitable or well- organized. Think freely and broadly. You just want to develop a list of possible avenues for further consideration.