First, if appropriate, heat up what you're canning. In this case, we're canning pizza sauce, so we need to make it hot.
In the meantime, check the petcock/counterweight hole on the canner's lid. Can you see daylight through it?
I hate to use a 7-quart canner for only 4 jars, but in this case that's all I have to can.
Check the gasket for the canner's lid, making sure it's properly lined up, then turn the lid on tight. This is hard to do with our canner. I do the best I can. The less tight, the more likely it will leak and drip water onto your stovetop, which is no big deal so long as it doesn't drip too much and you have enough water inside.
When the time's up, turn off the burner, remove the canner from the burner and let it cool. Don't try to take off the pet cock until the pressure has relieved or you may get burned. Ditto, opening the canner. Probably the best thing to do is something else so you forget about it for a while. After it's cool, open her up and remove the jars. Presto!
By the way, you can remove the rings now. If the lids have properly sealed, the rings are no longer necessary and there's no need to keep a huge supply of rings around. And -- if I've messed up -- let me know, please.