To begin with, you just need to click on "Get Started"
To create a new mind map you need to click on "Create a new map"
You can add nodes by clicking on any of the three nodes with the plus sign; add images; change the colour of any node; attach files, etc.
To finish you can save you work and download it as an image, a PDF file, or many other options.
The creator of this guide has not included tools