Digital scanners have quite a learning curve to understand and program. I would suggest that you download the software program FreeScan (which is free) to program the 396XT.
ScanNow.org - The Home of FreeSCAN! and use it to program your scanner.
There may be a learning curve with the software too, but nothing is simple with these new scanners. I suggest you download the program an become familiar with it. See here for help with FreeScan.
FreeScan User Guide - The RadioReference Wiki
I have made a FreeScan zipped file for Ada County/Boise which is attached. Download it to your PC and unzip (decompress) it. It must be unzipped before it can be loaded into the scanner. Windows Vista or Xp has built-in software to unzip the file. With the software you can edit the file I made. All of the data in this file was downloaded from the RR database.
The file I made has Ada County conventional frequencies under SQK 1; IIMARS Digital P25 system under SQK 2; State Police SQK 3; and Canyon County SQK 3.
Here is the location of the State Police frequencies. They are not P25 digital.
State Police Scanner Frequencies and Radio Frequency Reference
I hope this helps somewhat.
Dave