Queues are the mechanism for accessing music on the iPhone or iPod Touch.  Queues are accessed by pressing the button on the lower left-hand portion of the main screen.

Simply selecting an existing Queue for immediate playback.  Tap on the Blue Button to edit the Queue Content.

Select Edit to add or delete or reorder Queues.  Tap on the entry to rename.

Press the '+' button and select the type of Queue to add and follow the additional screen prompts.