First, make sure you are signed into Bubbl.us, and the Mind Maps tab is selected.
To create a new mind map, clicktap the button. A new mind map will open in the mind map editor.
To edit one of your saved mind maps, simply clicktap on the name of the mind map you want to open. Your mind map will open in the mind map editor.
Note that you can open multiple mind maps by opening one, switching back to Mind Maps tab, and opening another.