Canning is easy if you follow some simple rules. First thing I do is get the critters out of the kitchen. One hair in the wrong place will spoil a jar.
Take a few minutes and clean the kitchen. Make sure you have enough counter space. Use Clorox water and wipe counters down and clean anywhere there may be dust or a spider web that could fall into your brew. Clean up your dishes and put them away. Sweep up the floor. This can be done the night before, but I'd wipe off the counters again before you begin.
Now you have lots of room and everything is mildly disinfected. You need to estimate how many jars you will need for whatever you are making. Boiling water bath canners take 7 quart jars. I'd put them in the sink with soapy water and a little Clorox along with enough rings. Inspect your jars. Something my mother neglected to tell me at first. If there is even a little nick in the edge of the jar, throw it out, use it for a planter, whatever, just it's life as a canning jar is over. If what you are making is going to take you past lunch I'd wait to soak the jars until after lunch.
You should have a pot of what you are going to can and soaking jars. Clean the jars and rings well. Boil some water and slowly pour the hot water into the jars. I use enough to make the jars hot and be able to swish around the hot water onto every part of the jar. About half or three quarters full. You must warm the jars before you just dump boiling water into them. They can and will break. Just put in a little at a time and allow the jar to warm as you do it. This also heats the jar if your mixture is hot you are putting into it.
This is the time to put the canner on the stove. Fill it with water about half full. What you want to avoid is temperature extremes on the jars. Heat your water until it is approximately the same temperature as the jars. If you are cold packing, don't heat the water at all.
Now this has always been the tricky part for me. Get a small sauce pan with water and put in your lids. You want to lightly boil the lids. Don't over boil, don't under boil. I find that Ball lids need boiled a little longer than cheaper lids or Kerr lids.
While that is coming to a boil, (Make sure you watch them.) fill your jars. Dump the water out of each one as you go. Fill almost to the top. They call the inch at the top "head space". Some recipes want you to burp the jar. That just means take the extra air out by pressing down on the fruit or tomatoes. You want the edge of the jar to be squeaky clean. Wipe the jar with a paper towel. I then take the palm of my hand and twist it on the edge just make sure I'll get a good seal. Set aside until you have all of the jars filled.
Watching your lids??? OK after they have boiled for a little, take a pair of tongs and grab one. Put it on a jar and tighten a ring onto the jar. Tighten it completely and then turn back a tiny bit. Repeat on all jars. Put jars into basket that comes with the canner and lower it into the canner. Remember the water temp should be close to the temp of the jars. My jars sometimes float. I put something heavy on them. I have a little trivet that is perfect. You can find something that is boil-proof. Your water should be over the top of the jars. Bring it to a boil. Start counting the time for your recipe when the water boils.
When the time is up, I usually just let the jars sit in the water for a little.
If you have another batch to do, you have to be careful of the temperature extremes
again. I prepare counter space for the jars. I put several layers of newspaper.
It absorbs the heat well and you avoid putting hot jars on a cold counter. The
counter space must be out of the way of drafts. Cool air on hot jars is a no-no.
Drafts also include children rushing by. As the jars cool, the lids seal. You
will (most of the time) hear a loud pop. They are sealed when the middle is
sunken in. I keep mine out for a while to make sure they don't unseal. Some
people stand them up on the lids and some people remove the rings. I only remove
the rings if I run out for another batch. Store your bounty in a cool, dark
place. Bottom of a cupboard is fine. Cellar is better.