How do I configure the installer setup (ISU) options on the T6 Pro thermostat?

To access the Installer Setup (ISU), press and hold the CENTER and down arrow buttons simultaneously for approximately 3 seconds to enter the advanced menu. Press Select to enter ISU, then press Select again to cycle through setup options. Use the up and down arrow buttons to change values or select from available options. Press Select to confirm settings or Back to ignore changes. To save all settings and exit, press Home to return to the home screen. The manual contains a complete list of all ISU parameters on pages 8-10.