The toolbar gives access to the other windows in the Boa Constructor application. You can hold the mouse pointer over the different icons and help tips will appear. These help tips will tell you what the buttons do.
The notebook (or tabbed pane) provides a set of components which you can use while building your applications. The components are grouped for logical access.
The first group of components is called 'New'. This group provides components for creating new windows in applications. One of these icons, as indicated on the screenshot below, is used to create a new application. The new application consists of the application source file (wxApp1.py) and the initial frame (wxFrame1.py).
The application file is used as the starting point for the application. The default new application simply loads the form. The form is a blank form. You can add components to this form.
Boa constuctor opens the source code for the new application and the
new form in the Editor Window.