The Commands Queue contains all the commands that have been recently sent by the Business Server to each Workstation. Each computer should have separate commands in the queue. The Workstations connect to the business server and request new command every few seconds. A new command that has been recently generated but the client didn't receive it yet is marked as Pending. A command that has been received and executed by the client is marked as Sent.
To view the commands that are related to a task, go to Admin Tasks, and in the right column - Commands in Queue should show the number of commands related to that task. Ussually it is zero, but right after an action on that Task you will see a number of generated commands. Clicking on that link will show the actual generated commands.
When computers are offline, if you generate commands for them, these will remain in queue until the computers come online, download and execute the commands. It might be usefull sometimes when those computers will never come online again, or simply you issued by mistake a command for them to cancel that order. In this case you could delete the Commands Queue. To clear the queue go to Tools / View Queue and click on the Clear Queue button.