The timeline is used for visualizing specific events on yearly time basis.
For data, the "templateOptions" attribute is used and it's an object which specifies which fields from the business entity to be used in the timeline. For example:
{"id": "id", "title": "selfno", "subtitle": "selfno", "date": "datecreated", "description": "selfdesc"}
The timeline can be horizontal or vertical. This customization can be set in the "Orientation" attribute.