Take things slowly - do 1 system at a time, and backup at each point where things are working the way you want. Then if something gets hosed - we've all done it - you can revert to a previous working version
You might want to Google Uniden BCD396XT Complete Reference.
While for the portable version of the 996XT, the programming is virtually the same. It is a pretty in depth document. The good part about having the electronic version is that you can search when it opens in Adobe Reader.