Alt+G is a keyboard shortcut most often used to access the Design tab in the Microsoft PowerPoint Ribbon.
How to use the Alt+G keyboard shortcut
Alt+G in Microsoft PowerPoint
In Microsoft PowerPoint, the Alt+G keyboard shortcut opens the Design tab in the Ribbon. In the Design tab, after pressing the shortcut, you'll have the option to press an additional key to select an option in the Design tab. For example, after pressing Alt+G if you press S, it would open the Page Setup window.
Related keyboard shortcuts and keys
Below are links to related keyboard shortcuts and individual key pages.