Scheduled Call Backs will will show on your built in SalesSling Calendar - but they are also summarized for the day within the Notification Bell.
The Notification Bell is located on the far upper right corner of SalesSling - between the Calendar and User Profile.
FYI:
The notification Bell also shows Voicemails, and options for managing them.
Here is an example of the Notification Bell - with an upcoming Call Back reminder:
In addition. a small reminder will show up to remind the Agent of the scheduled Call Back - as shown in this example:
(it won't interfere with an ongoing call - but if you are not on a call and click on it it will show your upcoming reminder)
