When you pass the mouse pointer over a tiled button for a second or two, a one line bubble help clue is popped up giving the full name of what the tile represents. The menu bar located under the main window's title bar organizes most of the commands and features of the editors. A pull-down menu appears. Drag the mouse to the desired command and then release button-1. The menu is dismissed and the command is executed.
Some menus contain nested submenus, called cascading menus , that work in a similar way.
You cancel a menu by moving somewhere outside the menu and then releasing button-1. You can see in the text of the menu entries which commands have an accelerator. Some menu entries contain check buttons that indicate that a certain property of the editor is switched on or off. If you select this entry, the value of the property will be inverted. See for example the Show Page Boundary entry in the Page menu.