I want to be able to integrate with timeline module to put additions to timeline. It seems the modules that do this have a 'relations' array in config.php .

In the enable section

    'update_relations' => 1,

 Then, there is a section

  'relations' => array(
  	'bx_timeline',
  	'bx_notifications'
  )

I would like to understand these.

And what all is necessary to send notifications, add to timeline, etc.