As guest you have only limited access to the available information.
You can login by selecting 'login' in the top right of the screen.

Below is an overview of the applications that are available for you. In the top of the page is a selection toolbar of applications you can select to switch so you don't need to go via home. Only applications are shown for which you have appropriate authorization.

Each application has its own settings, where things like colors or opening preferences can be configured. You can open the settings dialog using the link at the top right of the page. Portal wide settings like idle timout or password change can be set in the 'home' settings ('home' is the application you have currently selected).