This is the default view and displays all colours. It shows the colour as an image, the name and the HEX and RGB codes for the colour.
Click on the colour box to display more details about the colour.
The other Gallery views are used to only show the light mode or dark mode colours.
Switch to table view to see all the details for all the colours, click on the colour name to see the additional information including how to use the colours in your page (see details below)
These are displayed when you click on the image in the gallery view or name in the table view.
To add the Headline and 'Today's Tasks' examples do the following
Click on the Headline you'd like to copy and some code will appear, copy this.
In the Notion page whereyou want to recreate this headline, type some text, highlight the text and a menu will be displayed. From this menu click on the 'create equation' button.
Paste in the code and add your own text in the code, replacing where it currently says Headline or today's tasks