How to configure Time Left Queue?
Time Left Queue works only if you setup Due Date/Time either through Workflow Assignment Values or SLA.
To setup Due Date Time based on a specify criteria, Goto Setup > Workflow Settings > Workflow rule > Create rule
with a criteria and Save the Workflow Rule.
Create New Workflow Assignment Value with Due Date Time.
Or
If you want to create Due Date Time using SLA, Goto Setup > SLA Settings > Specify criteria to match and setup Due
Date Time.