af5rn is on the right track. Forget everything you thought you knew about previous scanners. The memory archtecture of the Uniden DMA scanners (BCD396T and BCD996T) is nothing like you've ever seen before in a scanner.
First, I suggest you take some time to study these links from the wiki:
http://wiki.radioreference.com/index.php/Uniden_DMA_FAQ
http://wiki.radioreference.com/index.php/CategoryMA_Radios_Hints_and_Kinks
After studying those documents, take one system at a time. I won't walk you through all of the steps, because you need to learn how to do it and I'm bound to skip something. You can use either the software to do this or do it manually. I highly recommend going the software route. Also, other programs, like ARC396, will let you download the system parameters and talkgroup IDs from Radio Reference which really simplifies the programming process.
You say you are in the Indianapolis area, so let's say you want to montor the current MECA system. Let's think for a minute about how you are going to organize the scanner. First, you need to create a system that is a Motorola 800MHz Type II trunked system. The only frequencies you need to enter are the MECA control channels. You don't need to enter all of the frequencies used by MECA because your scanner can figure that out on its own. Make sure you assign a system quick key to this system so you can access it easily from the front panel.
Once you have the system created, you need to set up groups within that system. Let's say you create a group for IMPD, another group for Indianapols Fire, and another group for Marion County Fire. You can create 20 groups within one system, so you have lots of flexibility. Each group can be assigned one of 10 group quick keys. If you want to break up the IMPD talkgroups into their different districts, can do that by using separate groups.
OK. Into each group, you'll program the talkgroup numbers and names for each group you want to hear. In your IMPD group, you'll have 24016 which is MET-NE1 and 24112 which is MET-NO1 and so forth. You'll go through this process to populate each of your groups with the talkgroups you want to hear.
Let's stop right here for a minute because there is an important point that baffled me when I first got my 396. System quick keys and group quick keys are different and they are accessed differently from the front panel. Study the manual and the various online documents until you understand the difference and how to access them.
Now, you should be able to exit the programming mode and start scanning. Use the system quick key procedure to select the system quick key that you assigned to your MECA system. You should see the scanner start picking up the MECA control channel. In fact, if you press the HOLD button, you should hear the control channel data stream and the scanner display should show you "SID" and "2723" which is the MECA system ID. If it doesn't then you've missed something. Press the HOLD button again to start scanning and the scanner display should read "ID SCAN". When a talkgroup you have programmed becomes active, the scanner should stop on that talkgroup and you should hear the traffic.