I realized recently that I've been writing "Prepare canner, jars and lids" on a lot of my posts, but I think I have yet to explain what that means, so in an effort to be helpful I'll make it easy (and then go back and link here from all my posts). Basically this is a "Canning 101" type post, so I'll explain everything.
Preparing Canner:
The canner is the big pot that you get. They're really cheap, likely because they're not made to put anything into but water (so please don't try cooking in one). They come with a rack for jars that you lower into a hot water bath, and also a set of tongs to lift hot jars out of the water.
All you need to do to prepare the canner is put water into it (enough that you'll completely cover all the jars once you lower them in), and put it on the stove to come to a boil.
I should also note... the cheap canners you can buy at your local big box store can't be used on induction cooktops or any flat top surfaces. I understand that for those types of cooktops you need to have a pot that has an entirely flat bottom, and a canner doesn't have that. You can buy flat-bottomed canners, but they do cost more. I knew there was some benefit to having a coil cooktop.
Preparing Jars:
You need to sterilize and heat your jars. Sterilize to kill bacteria, and heat them up so that when you pour hot stuff into them and stick them into boiling water that they won't break. I do this in the dishwasher. A regular cycle with a heated dry does the trick. Just make sure you time it so you can use them hot (feel free to take them out before waiting for the dry cycle to finish, as long as they're reasonably dry.)
Preparing Lids:
I don't usually do anything with the rings, since they're on the outside of the seal, so other than making sure they are clean and not rusty, they just wait until they're needed. The seals also need to be sterilized and warmed up (to soften the rubber part of the seal). You can't do this in the dishwasher because it will degrade the rubber, so I do this in a small pot with water. I bring it to a boil, and then turn off the heat, letting the seals sit in there to stay warm until they're needed.
A note on pressure canning.
There is also a type of canning for "low acid foods" but I'm not really familiar with that personally (I have yet to need it, since I don't have a garden of veggies to store, or the cash to buy a pressure canner), but you can go
here for more information on that.