You can confirm each pick stop on the load before finally confirming for the load. You can confirm stops as they are (without changing the composition of their containers) or make changes before confirming (if you are a non-restricted user).
You must confirm the stops in the order in which they occur. In other words, you can only confirm a stop if the stops before it have been confirmed.
The MBOL number is established for the load when the first stop is being confirmed. Once the first stop has been confirmed, it cannot be changed.