The main window includes a menu bar at top of the window. To see the contents of a menu, move the pointer over the menu keyword in the menu bar and press or click the left mouse button. The menu will open up below the pointer, after which you can move the pointer to the desired menu item. If you pressed the mouse button, select the desired menu item by releasing the mouse button when the pointer is over that item. If you clicked the mouse button, select the desired menu by clicking the mouse button again when the pointer is over that item.
You can see all of the menus with a single mouse press or click; you don't need to press or click the button again when moving to a different menu, just move the pointer to that menu and it will open in place of the previous menu.
Some menus contain additional menus. These additional menus are indicated by a small right-pointing arrowhead on the right side of the menu item. When you move the pointer to one of these items, another menu will open up to the right of the already-open menu. You can then move the pointer into this new menu in order to select an item from it.
Some menu items have a label which ends with an ellipsis, like this: ... This indicates that selecting that menu item will open a dialog box with additional questions. No other action will be taken for these commands until specified by accepting the dialog. Menu items which do not end with an ellipsis may take immediate action when selected.