In the website builder you can add, edit and remove all different sections featured on your website on the left hand side of the preview image.
You can see more information about editing and creating website content here - https://gettingmarried.co.uk/what-content-for-your-wedding-website/
You can also find out more information about creating a bespoke design theme here - https://gettingmarried.co.uk/creating-a-bespoke-wedding-website/