The General page of the Preferences window includes options to control the Dock icon, status menu, and more.
Automatically start...: Time Out is most useful if it's always running, so it's a good idea to have it automatically start whenever you log in to your Mac.
Show the Time Out icon in the Dock: By default the app appears in the Dock, like a normal Mac app. This means it has menus in the menu bar, and appears in the Cmd-Tab app switcher. This makes it easy to find.
Don't include Time Out in the Dock: If you prefer, the app can be hidden from the Dock and Cmd-Tab switcher. It won't have menus when operating in the background like this, but all functions are available via buttons in the Preferences window. This option is available as a reward for supporters, but like the other rewards, you can try it for a short time as often as you like.
Show Time Out status in the menu bar: Checking this option will display a status item in the right of the menu bar. The status item can display an icon and/or countdown. The icon can be a variation of the app icon, or (more usefully) the label of the next due break. The countdown can be represented in various ways, or you can show the time of the break. This is also a supporter reward.
When the status item is displayed and the Dock icon is shown, clicking the status item will toggle the Preferences window visible and hidden. When the Dock icon is hidden, clicking it displays a Status popover that is like the sidebar of the Preferences window.
Absolute dates / Relative times: The list of breaks in the sidebar (and status popover) can be displayed as absolute dates and times, or relative number of seconds, minutes, etc.