Place the roast in the crock and pour the carrots, onions and mushrooms around it.
Mix the remaining ingredients in a separate bowl to make the sauce, then pour it over the roast and veggies.
Cook on low for 10 hours. The internal temp should be about 200 degrees Fahrenheit.
When it's done, it will look like the tomato paste solidified on top of everything. There is nothing wrong with this, simply remove the roast and stir the tomato paste into the remaining sauce, then ladle the sauce over everything when serving.
Notes
Please note that the nutrition data is a ballpark figure. Exact data is not possible.