If a TA is currently accepting requests for help, the first line of the applet window will say "The queue is active." Fill in your name and the name of the machine at which you are working (every machine in the CADE Lab is labeled with its name). Click on the Add button—your name and location will be added to the queue. When it is your turn, the TA will come to your machine and help you. Be prepared to ask your question when the TA visits your workstation. Do not expect the TA to wait around while you try to make a particular error appear.
If you decide you don't need help after all, click on the Remove button to remove your entry from the queue.