normal workunits, you should only have 1 in the queue, because it's downloaded in one piece, and worked on, then uploaded. If you're in queue 3, that means that you've already had two downloaded, worked on, and uploaded, whatever the results, or, if you've already done 10 workunits, it means that you're on your 13th, or 23rd, or ....
Queue's come into play, if you've selected timeless work units, where only portions of the workunit are downloaded at a time, you work on one, the results are saved, then you go onto the next. Once you start the next, the results from the previous queue are uploaded.
But this should only be used for EXTREMELY slow workstations, or those that are turned on and off several times a day, and aren't processing 24x7, or those that have sporadic internet access.
I think he means there's one in queue #3, not 3 in queue. It's the one he's working one. This machine I'm on has it in Queue #6.