When editing any entry on a section you've allowed Social Poster to appear on, you'll be shown a small widget to the right-hand side on your entry.
Each properly configured account will appear as a tab on this widget. Each tab has a small indicator alerting you of its status: Green is enabled and will post, Clear is disabled, Red is an error. All defaults as defined in the plugin settings will be loaded in, which you are free to change.
When an entry is saved, and its status is set to live, Social Poster will trigger a post to each account you have enabled. This will only occur once, and if successful, will load in a note in the widget panel. Should you wish to manually post to social media again, you may do so, but is turned off by default.
Likewise, if an error occurs, your post will not appear on social media, and a description of the error will appear in the widget for the account.