There are 2 things I would get started with - note that here, and in the wiki links below, anything in blue is a link...
Uniden DMA FAQ - The RadioReference Wiki
BCD396XT < UnidenMan4 < TWiki
Note that while the DMA FAQ largely concerns itself with the pre-XT models, the concepts and explanations remain valid. If you learn about these, making the jump to the XT models is a short logical jump.
Read the FAQ carefully, and investigate everything that's tagged as a link. There's a great deal of information here; get your favorite hot beveridge, get comfortable and begin reading. I would also get to the NJ forum and see if someone can give you a file that you can examine by using FreeScan. This freeware package is mentioned in the FAQ, and it can import ARC (BuTel) and UASD (Uniden Advanced System Director) files, as well as it's own native (.996) data formats.
You didn't say what part of NJ you're in - please add that via the User CP. It's going to be important - there are many differences in hearing stuff in the South then North. I'm from Bergen County myself....
73 Mike