Volume imbalances are areas in the price chart where no trading has taken place. They can occur when the market closes for the weekend and then opens for a new week. They can also be caused by sudden, fast market movements in response to unexpected events or high impact news releases such as financial reports or policy changes. This sudden shift in market direction creates a 'gap' or 'vacuum' in the price chart, and this is what we refer to as a volume imbalance. See the example below:
To enable the feature simply head over to the indicator settings.
When you are inside the SMC settings - locate the "Imbalance" section and make sure to check the Volume Imbalance is checked as shown below.