1. How to create a queue
Settings -> Business Management -> Queues
2. How to assign a queue to team or user
Settings -> Business Management -> Queues
3. How to assign items to a queue
Workplace -> Activities-> Tasks -> Save -> Add to Queue
4. How to assign queue item to an user
Who is working on: Workplace -> Queues -> Item -> Queue Item Detail
5. How to enable an entity to a queue
Settings -> Customizations -> Customize the System -> Entities -> Queues checkbox