There is no special toolbar support in XMA. You cannot define a toolbar in guidesigner. But you can use the SWT classes ToolBar and ToolItem in your code.
In guidesigner you can use a composite as placeholder at the position in the page where you want to place your toolbar.
In your code, you overwrite createWidgets() to add the toolbar to the widgets of your page. You have to call super first, to create all the widgets defined in guidesigner. A ResourceBundle will be needed to externalize your texts into a property file for internationalization. The composite you created in guidesigner as placeholder will be used as parent of the composite. If you give no layout information, the toolbar will be placed top left into this composite.
It is important to use XMASelectionAdapter as listener, because it disables the creation of SWT events by XMA during your event handling code (see SWT Event-Handler). Additionally it adds exception handling code.