When you're starting your research, you need to have a balance between brainstorming and looking for external sources.
On the one hand, you want to be able to feel out what you already know and explore what you think sounds like an interesting idea.
On the other hand, you want to make sure you're not going too far in the wrong direction while you're still at the starting line.
It can be tempting to think you'll save time by diving right in, but taking the time to do your background research will help in the long run! Benefits include:
Mind maps are useful for capturing the connections between your ideas and revealing where you might have discovered more layers of information. You can record ideas going from broad to specific, or vice versa. As you do your background research, continue to take notes on your mind map to help flesh it out.
All the mind mapping exercises described above are to help you develop and narrow down your topic -- the general idea of what you're going to be researching. From that, you need to develop your research question, i.e. what is the question you are attempting to answer by doing your research? This, in turn, will form the basis for your paper's thesis.