The Commit Trade feature is used when creating Trading Positions. It effectively moves any trades entered into the Option Chain "Model" column to the Open "Position" column. For detailed instructions on this process, see here.
If no Trades have been entered into the "Model" column of the Option Chain screen area then the "Commit Trade" button does not do anything. However, if a Trade has been entered into the "Model" column then the "Commit Trade" button will move that trade over to the "Position" column - this is the equivalent of executing the trade, but for back-testing purposes.