All the boxes of content seen here on the startpage are what we call blocks. A block is essentially an area with content of a certain type. Some examples of types of blocks are Featured article groups, Full-width article - or Custom HTML. All blocks can be edited, moved och deleted. When you create a block, you choose which type of content it consists of. You can try editing this block by finding it under Content > Startpage.
Above this text you can see a block of the type Connected articles.
You can have as many blocks as you like and fill them with what you want - it's totally up to your imagination.
Go to Content > Startpage to build your own, beautiful startpage.
PS. Don't forget to press the green SAVE-button to save your changes.
Try removing this block by clicking Remove down to the left (when you are in the admin interface).
Attention: A removed block cannot be restored, but you can always create a new block and fill it with the same content again.