To set messaging costs, open your Messaging Setting tab. There, you can determine how much subscribers and non-subscribers will pay to message you.
To activate your Directing Messaging and show fans that you are online and ready to DM, you must have your Message Dashboard open.
Please keep in mind that the counter will begin when a message comes through. Therefore, if you have more than one tab open, be careful not to lose track of time. On the flip side, if you answer messages quickly, this can increase your earnings.