Post install: Stuck in "Preview" with no Admin Console

Just installed on Ubuntu and after initial, and created a new user. Looks like I’m in “Preview Mode” after seeing “Preview Mode: Email notifications have not been configured” at the top of my screen. Sooo. How do I 1) access Admin interface, 2) enable normal mode, or 3) access the config file to otherwise enable email and normal mode. Thanks!

see [Solved] No System Console when logging in with GitLab to add a user as system admin.