There's very limited use of encryption (DES-OFB, not ADP like that thread says), so that's not the problem. As a fully digital system, there's no tones to input. Instead, there's a NAC, a 3-digit identifier that is basically the PL tone equivalent for P25. Enter that value in the NAC column for the channel (which, for some reason, isn't visible in Simple View), and the audio type will be set automatically to Digital Only. If the NAC isn't listed, leave the NAC field blank and set the audio type to Digital Only.
The end result would look something like this: