I have a 163, and just programmed it to trunk my largest police department where I'm at. It's like non-stop chatter.
You really just simply press "SCAN", then "MAN", and type in your control frequency then press "ENT". You can press "TEXT" and type in a short description, press "ENT" after. Then just hit the up or down arrow and do the same to type the others in after that.
Once that is done you need to program the talk group id's. Press "PROG", then "TRUNK", and then enter the id #, then press "ENT". You can press "TEXT" to type in a description of it, press "ENT" after. Use arrows to move to another space to program another id.