Here's what you do:
1. Wash your tomatoes and get rid of any unwanted bits.
2. Pop them in the blender. Blend for a few seconds. It doesn't have to be pureed, you just want it chopped up.
3. Put in a pot on the stove, and bring to a boil. Keep adding crushed tomatoes as you blend them up.
4. Sterilize your jars and lids by either a) pouring boiling water into/over them or b) letting them sit in the boiling water in your canner until you need them. I find b less work because you already need to boil the water. You do need to sterilize the tops in a separate bowl though. Not sure why, just do it. :)
5. You can let the sauce boil for a couple hours if you want it thicker. I personally prefer them as little processed as possible so I just bring them to a boil and have at 'er.
6. Hot pack the tomatoes. That means you pour hot tomatoes into hot jars. Add 1 tbsp lemon juice and 1 tsp salt per jar (this helps bring the acidity up to help preserve them safely).
7. Clean off the tops, pop on the lids, and put in the boiling water*.
*I prefer to pressure can my tomatoes, since I feel like it's safer. If you have a pressure canner, obviously follow the directions in your manual for tomatoes. I do mine here in Edmonton at 12 lbs pressure for 25 minutes.
8. Make sure the water is above the tops of the jars by at least 1/2 inch. Once the water returns to a boil, let the jars boil in there for 45 minutes. When done, turn off the water, let it cool down for 5 minutes, and extract your jars. Over the next couple hours they will cool down and you will hear the delightful "ping"** that tells you they are sealed!
**Are you lucky enough to have some of those glass lids? I LOVE those for tomatoes because it means that zero BPA is leaching into my tomatoes. I learned the hard way that you have to put the rubber ring on the glass lid BEFORE putting it on the jar. Sterilize them both in a bowl, together if possible. And when you're done, be especially careful to move the jars as little as possible until they are cool. You obviously won't hear a "ping", so you'll have to remove the rings (which you're supposed to leave off) and give the lid a little tug. Those things hold like crazy, so if it comes off with mild hand pressure, it's not sealed. Either do it again or put it in the fridge to use up soon.
Ok, just one more thing. If you DO want to take the skins off and have a day before you want to do the canning, here's something I discovered last night. Pop them in the freezer for the day. When you're ready to deal with them, put them in a sink of hot water and BOOM the skins will slide right off! WAY less work than boiling for 2 minutes, then putting in a bowl of ice cubes, then getting third degree burns while trying to peel the still-hot tomatoes. Never will I skin tomatoes the old way again!
I learned my canning method from her cookbook,
"Family Feasts for $75 a week", which, incidentally, is an excellent cookbook for learning how to cook from scratch.