If you start off with a blank map, double clicking on any of the bubbles with words allows you to rename them (like renaming a folder on your desktop). Somewhere up at the top (left, I think-I'm away from the computer) there is a plus + symbol. Clicking on that allows you to add new "nodes" to the bubble you have highlighted. I'll get back to my computer soon, if you have any additional questions, feel free to send me an e-mail and I'll do my best to help you. It took me a little while to get used to it too. If you've got a smartphone, the app is in some ways easier to navigate.

Hope that helps