I HIGHLY reccomend you download win96 from
www.starsoft.com
It will allow you to program your scanenr from your pc.
You will need to purchase a 25 dolar cable from radio shack but it is more than worth it. It is product number 20-289 DO NOT let them sell you any other cable. None of them work. 20-289 is what you need.
This will help you tremendously.
As for your poblem.
The differences are in the types of systems you are programming in. Take a look onthe first page of this site. there is a wealth of information on trunking and how it all works.
I am still learning new things everyday but you will really need to apply yourself and buckle down on it and you will have it all digested in no time.
Good luck..