Throw all the ingredients into your slow cooker.
Give it all a few good stirs.
Cook on low for 6 to 8 hours, or high for 4 to 5. It's a good idea to stir occasionally if you can to redistribute the seasonings. About 30 mins before you turn off the cooker is a good time to adjust seasonings so they can absorb - more salt if needed, maybe a pinch or two of sugar if your tomatoes are extra acidic, maybe a dash of Balsamic or extra Worcestershire if your tomatoes aren't tangy enough...
A warning about high setting - it can get pretty hot depending on volume & surface area. I have an 8.5 quart slow cooker, which means greater surface area and, as a result, a higher heat for the volume. At 4 hrs on high, I could smell the sugars from the tomatoes and ketchup going from caramelized to burnt on the sides. Less likely to happen if you have a smaller capacity cooker.
As a general rule, the lower the volume and/or the greater the surface area of the cooking vessel, the less the cook time. And there you have it. :)
Enjoy with pasta of choice.
