In the Op column you enter the operation number. By default, the first operation will be 10 if no prior operation rows exist on this part.
If you open the Time Calculation from an operation row in the Preparation procedure, the operation number will be the same as on that operation row. If you enter a new operation number, this will create a new operation row in the Preparation. You can also enter an existing operation number. You can also have the same operation number on several rows. For example, during turning processes when you might need to add several processing rows for a single operation, to include both axial and radial processing, as well as beveling.
The calculated time from the Time Calculation for the entered operation number is saved to the operation row with the same operation number in the operation list in the preparation.