In the latest version you can access the templates (such as the Ancient History one in the linked example) when you create a new timeline.
Once you click on “New Timeline”, a list will appear on the left panel that says “Choose a Template”. This lists different categories such as General, Fiction etc. Clicking on these categories will then give you a list of different types of templates for that category.
For example, if you click on Historical, you will then get a list with “Ancient History”, “Classical Music”, “Political Timeline” etc. Clicking on the name of the template will load it, and then you can click the “Use this template” to begin using the template for your timeline.