The Content Block component designates regions on the page where pre-styled instances can be inserted in Content mode.
In Content mode, you can edit content inside this Content Block and add new instances predefined in templates. Content outside Content Blocks is read-only.
To predefine instances for insertion in Content mode, switch to Design mode and add them to the Templates container.
To insert predefined instances in Content mode, click the + button while hovering over the Content Block on the canvas and choose an instance from the list.