To add a Linked Calendar, please do the following:
Click on the "Manage calendars" link in the left side menu.
Select a source from the "Add calendar" dropdown menu in the "Linked Calendars" section.
Select a subcategory.
Select the target information (if available) and click on the "Add" button.
The added Linked Calendar will appear in your Calendars list where you can edit it using the "Edit style" link, or remove it from your list by clicking on the "Remove" link.
Events belonging to this Calendar will be displayed in your calendar in the color selected after clicking on the "Edit style" link.