The queues and/or waiting lists you are to handle are seen in Queue status, opened via Menu > Queue status or q.
For best overview you might want to sort the content. Click on header Type to sort by services, i.e. the combinations of type of contact channel and distribution, such as 
Callback from queue and 
Callback from waiting list.
Select queues and waiting lists to serve
Requires that your role contains the Execute login/logout for specific queues access function.
You can select which queues to get contacts from, when your status is Paused or Ready and you do not have any ongoing contacts, by clicking on 
Select queues to serve in Queue status.
An action column is then displayed.
To log out from a queue, just remove the check mark.
A queue without check box is mandatory to serve.
Mark to serve.
Close the editing mode, by clicking 
.