Let's start from creating a new model. Login and go to the My projects page. Click the New project button. You can rename the project as you want. Then click on it to open the model editor.
The editor window contains of two parts. On the left pane you can see the model tree. We will refer to it as model page. The right pane, called details page, shows the details of the currently highlighted node on the model pane.
Initially, the model contains only a single root node. It has the same name as you called the model on the My projects page, but in general those two names are independent. So changing this name will not affect name of the model as well as changing the model name will not affect this node. Lets' rename the model to Tutorial, just to confirm that. You can do it using the text box on the top of the model details page.