Bubbl.us is a free tool on the internet to help you create your mindmap. It's free to use and get started, though there is a paid version that has more features. The free version has everything you should need to make your mindmap.
Bubbl.us has a brief tutorial on how to use their tool.
Now that you've done some background work (pre-research) on your park, you're ready to put together your search strategy and start finding sources.
This will require more focused research than the pre-research step. Each point you're required to include in your project will be its own information need and should be researched separately.
A mindmap can help you visualize the information you need and see how it's all connected. You can also use it to keep notes on the sources you find.
Below is one example that used Bubbl.us to create a mindmap. You could also create your mindmap on paper. Whatever method you choose, start with your park in the center, and build it out from there!
In the mindmap below, the national park is at the center with branches for each piece of information you are required to include in your project. On each branch of those you'll see keywords or even sources with a note about which database they were found in.