Click the user menu on the bottom left corner and select Settings.
Here you can check/set your timezone, preferred currency and CSV (order file) export delimiter. These settings can be changed anytime and are remembered until you change them again.
Changing the timezone affects ALL times you see on the Dashboard, including those for planned tours. For example, a tour planned with timezone set to Western European Time (UTC) starting at 2:00 pm changes in the Assignments panel to start at 3:00 pm when the timezone setting changes to Central European Time (UTC+01:00).
HERE recommends you set the timezone to match the depot from which tours are run.