Mapping is a writing technique that is meant to visually organize your thoughts so that they flow better.
To use the mapping technique you should first start with a general idea or topic that you are writing about. Write it out and put it into a box or circle on the page. Many people put this in the center of the page to leave room for branches, but if it makes more sense for you to put it elsewhere, please do.
The next step is to "let the ideas flow out of you." On a separate sheet, in the margins of your first sheet, or in the empty space around your topic box, write down any ideas related to your topic. Try to write as many as you possibly can.
When you're done, go through what you wrote down and select the ones that are MOST related to your topic or on which you can write the most. Write these selected ideas around your topic on the original page and connect them to the general topic box/circle.
Go through each of these new ideas individually and repeat steps 2 and 3. Think of ideas related to each of these, write them down, select the ones most related or best suited for your topic, and put them on your map near the first idea. Continue doing this for each new idea on your map until you have enough content to write about.
This method is very good for visual learners who need to see the story and ideas before they can start writing about it. And don't worry; you aren't limited to what you map. If you think of better ideas later or decide one of your original ideas doesn't work, change it! Writing is an evolutionary process.