First, brown the beef in a skilled, then add it to the crock pot. Dice all your vegetables and add to crock pot, making sure to dice the serrano chilies as fine as possible, to maximize the flavor.
Next add your cans of tomatoes, beans and tomato paste, undrained. Add beer.
Top the mix with the spices, mix thoroughly, let it cook in the crockpot on low for 8-10 hours.