Once a campaign has been released, the campaign will move to the Queued tab.
The only action that can be taken for a General Campaign is to use the Return To Draft option. Once it is a draft, you can take additional actions.
For a Segmented Campaign, clicking any of the linked items will move you to Segmented Campaign Home. You can view Version information. You cannot make changes to the Versions. You can Return to Draft from this area as well.
NOTE - a scheduled campaign can be returned to Drafts until 5 minutes before the scheduled date/time of send.
NOTE - messages set to "Send Immediately" cannot be returned to Drafts.
NOTE: the Audience number shown doesn't factor in unsubscribes, invalid emails, etc.