OK its an PSR-800?
PSR-800 - The RadioReference Wiki
Check here to get you started with it. Its a big leap up from the old days ... But it is actually pretty easy to set up.
This scanner will let you get in n the MSWIN and be able to identify the new TG's for CCSO, CSPD, Copiah Schools, CSVFD etc....
The article in the wiki will set you on the path to happiness in monitoring with Object Oriented Scanning. Be sure once you get the hang of it to set up wildcards so you can find the unknown TG's....
If you'd like to learn more about trunking and P25 Trunking in general there is a lot of useful data in the wiki also, as well as the forums here.