Grinding To A Halt

Our garbage disposal is broken. It was making a terrible metal-on-metal grinding noise, but we're used to that. We toss at least one spoon a week in the trash after its noisy joy ride in the disposal. No, this was worse. The sound made me think of the "gnashing of teeth" that is referenced in the Bible.  I've never heard gnashing of teeth myself, but it probably sounds like grinding up teeth in the disposal. Before I could turn off the disposal it threw up some of its own parts and they landed in the sink. Game over. I immediately put a strip of duct tape over the switch on the wall, forever locking it in the "off" position. 
In a perfect world, I would remove the old disposal, put it under my pillow and wait for the Plumbing Fairy to replace it with a $100 bill, but my husband was raised on a farm, so his first instinct is not to seek professional help. Instead he announced I should purchase a new one and we would install it.

It's been three weeks, and I have done nothing. Something is telling me this wouldn't go well. I was disturbed by the above drawing showing a part called the "strainer body." There's no doubt I would strain my body installing this thing. I pop a disk just reaching under the sink for the dishwasher soap. And what's this thing called the "escutcheon?" Isn't that what our Spanish teacher used to yell at us in high school, to make us listen?
No, I can see problems ahead. I'm frightened of the thing called the "trap coupling." It probably grabs your finger and traps you under the sink until someone decides to run the dishwasher. Around here, that could be a long, long time.
I'll stick with the duct tape for now.