After you finish the setup wizard, you are on the dashboard in Timebutler, the home page that gives you an overview of the most important information.
You can now configure the additional settings. To do so, click Settings > More.. in the bottom left and work through the various configuration options on the page. You can leave most settings unchanged; only some options need to be adjusted.
You don’t need to complete all settings before you create the user accounts for your colleagues. You can also create the user accounts first and optimize the remaining settings afterwards.