social media sharing problem

I have just started a new website with wordpress and was aiming to use my twitter account to promote as have a few hundred followers from my writing elsewhere.

Yet, when I share my first post on twitter, it only appears as a static URL, no preview, I mean usually the twitter system recognise the URL and then below a featured image and first few lines appears in preview, which very much helps to share.

Can someone please help me work out how to share my posts with the preview appearing on twitter/facebook etc??

The page I need help with: [log in to see the link]