Q. How can I add the Marks button to the Toolbar?

Double click on the toolbar (basic) border, and the Customize Toolbar dialog will appear, where you can select the Marks button and add it to the toolbar. Alternatively, you can select Customize Toolbar on the Tools menu, and then double-click the Toolbar 1 in the Toolbars list, where you can select the Marks button and add it to the toolbar.