This step is hidden if in the Configuration Options step you set the flag No Known Parcels.
This step is used to add additional material types to Tactical Scheduler that may not be present in the reserves inventory. This may include legacy materials on the stockpiles, or known material types that are predicted to be present in future iterations of the schedule.
This ensures that the parcel filters on Destination Logic, Steps Logic, Constraints and Product Specifications do not have to be updated every time there is a change in the reserves.