Hi Iris, I agree with Bill, and would just like to add one other common use for 'here we go' which is to indicate that something bad is happening again: 'Oh, here we go (again), shouting (or moaning) at me as usual'. You might also join in singing 'Here we go, here we go, here we go' if you were watching a British football match and your team was winning. Also, there is the other quite similar expression 'there you go' which can mean 'well done, or that's correct'.