Once you send a manual message, you can check its report in Analytics - Campaign reports tab.
You can check a general report for all messages and review each of them separately. The general table displays the following:
Last sent date;
Sent (percentage of sent messages);
Read (percentage of read messages);
Clicks (percentage of those who clicked on a link in the message);
Percentage of unsubscribed leads.
Click "Report" to see its detailed report:
Message ID. It is used for message identification for different requests.
Campaign type: chat, small pop-up, big pop-up, email.
Last time sent. Last sending date and time;
Number of messages sent;
Percentage and number of read messages;
Percentage and number of message replies;
Percentage and number of those who clicked on a link;
Number and percentage of those who unsubscribed;
The number of spam claims.
Each of these points can be reviewed more detailed by clicking "Details" button. Or just move to Visitors tab.