The astronomical clock can be adjusted by the left control panel. The first group of controls allows you to set date and time, the second group determines the location and the last option switches the language of user interface.
Date, in the offered range, can be set by dragging the sliders. The clock is updated after releasing the mouse. Another approach it to choose a predefined event from the drop down menu. Back and forward arrows search for the previous and following events of the given type. Any movement of the sliders will automatically switch the mode into the 'Custom' one in which slider values are preferred.
For predefined events it is necessary to select the corresponding local time zone what ensures the correct time computation of the event in the given location. Time zones also carry daylight saving time (DST) information (a time shift and a date range). Astronomical clock aren't adjusted accordingly when DST is active which means there is a difference of one hour between the date set and the real one.
The design of the astronomical clock depends on the latitude. For both small and large latitudes the clocks cannot be built at all. The appearance for the rest of latitudes can be analyzed by choosing the corresponding value from the drop down menu. Negative values belongs to the southern hemisphere where everything is upside down :-)
More info about the astronomical clock with the guide how to read its different time values can be found at http://www.orloj.eu/