More to come, see our sample exhibits and copy the code for now.

If you want to have total control of the timeline, do this in your HTML code:

  <div ex:role="exhibit-view"
     ex:viewClass="Exhibit.TimelineView"
     ...
     ex:configuration="timelineConfig">
  </div>

Then add this javascript code

  <script>
     var timelineConfig = {
       timelineConstructor:
         function (div, eventSource) {
           ... construct your time line here ...
         return tl;
       }
     }
  </script> 

Obviously, change foo to whatever you want. To set the height of your timeline, do this inside foo:

  div.style.height = "400px";

Don't forget px.

For a full example, see this message and its follow-up.