Once you're logged in to your Gmail account, use NVDA's search function (NVDA Key+Ctrl+F) and enter "Settings" as your search string.  The first thing it finds is the Settings button, which is collapsed and places focus on it.  When you activate the button it brings up a dropdown list/menu and "Settings" is one of the entries.  That's the entry you should activate to get to all the settings you can tweak for Gmail, and there are a lot of those.
--
Brian

I worry a lot. . . I worry that no matter how cynical you become it's never enough to keep up.

         ~ Trudy, in Jane Wagner's "Search for Signs of Intelligent Life in the Universe"