To use the "Google Calendar" widget you must first make sure that the calendar you are going to show is set to public in the Google account. To do this you need to go to calendar.google.com and then select the Change Sharing Settings on the left hand side menu
This will then open a new window - where you will be able to turn on the public calendar option (radio button) - see the image below:
Once you have made this calendar public you will then be able to add the calendar to the Display5 show using the "Google Calendar" widget.
Enter the account name for the calendar in the "Google Calendar account" input field. You DO NOT need to add the @gmail extension. Next you can select to show or not show the title of the calendar.
The Calendar mode will display a daily, weekly or monthly view of the calendar. The "Timezone" field, ensures that you are showing the correct times and dates in the panel of your Show. You can also specify the start of the week (Mon, Sun, Sat) for display. The width and height allow you to adjust the calendar to fit the destination panel. You can add a background color, set the duration for this slide and optionally, schedule the slide.