To use baking soda to get dog urine out of carpet you should first mix 3 parts of water to one part of white vinegar and apply that mixture to the carpet where the dog urine is and then let it sit for around 5 to 10 minutes.
Then after applying the vinegar and water to the urine in the carpet take some baking soda and sprinkle it over the carpet where the dog urine is.
Then allow it to dry and then use a carpet shampooer to suck up the vinegar, baking soda and dog urine from the carpet.
You can also add some vinegar to the carpet shampooer and then use the carpet shampooer to clean the carpet and urine out of the carpet.
Then sprinkle some more baking soda onto the carpet to deodorize the carpet.