<p>I see that the SML/NJ includes a queue structure. I can't figure out how to use it. How do I use the additional libraries provided by SML/NJ?</p>

I don't have a complete answer for you but I could point you in the right direction. You should look up using the compilation manager (CM) which is built in to SML/NJ. You can think of it as Make for SML.
To use a library from the SML/NJ library you then add smlnj-lib.cm to the CM description file of your application. Then you can use the declarations such as Queue from that library.
The smlnj website has some documentation about the
compilation manager
.
Hope this at least points you in the right direction.