Question

I don't understand how they got final product

https://dega2pc35ccak.cloudfront.net/images/812d7fec-45d3-4c63-8de8-6ec7379bd1eb/image_attachment.jpg?dl

the top question. could you please show the mechanism/arrows on how the final product was achieved. I don't understand where the two new bonds connecting to the middle came from.