I am finding it pretty hard to edit the timeline. I can’t make the timeline description show or change the icon or edit the colours. Please could someone point me in the right direction?

It doesn’t show descriptions. Just the titles like it is shown in the demo.
The icons option unfortunately is there by mistake and will be removed.
What colors are you interested in changing? Titles and dates colors can be changed by going to Edit > Design in the widget. (headings option and font color option).