Your question is pretty vague, so I'm going to give a basic overview. If you still don't understand, feel free to ask any questions. All frequencies and talkgroups can be found here.
Worcester has an EDACS trunked radio system. That means that you will need to program all 10 frequencies, IN ORDER, starting with channel x01, where x is the bank you are using. You need to set the bank to EDACS mode. I'm not exactly sure how to do this, but you can consult this guide.
Now you must program the talkgroups. To listen to the Fire department, you are going to want the first 5 talkgroups to catch most of the action. For the police, listen to the first 2. There will be other things happening on the other talkgroups listed, but these are the main channels. There are many active city services and public works talkgroups listed as well.