In the Part Warehouses module, click the to expand the desired Parts Warehouse record.
In the Locations grid select the Location record you wish to set as Default for the Warehouse.
Click the Toolkit in the Locations grid and select Set as Default for Selected Record. The system will alert you to the number of records that will be affected by the action.
Click OK to proceed. The tool runs and sets the selected record as the default location. A check mark appears in the Default Location box next to the record that is the default location.
Note: There can only be one Default Location per Warehouse at one time.
How to set a default location
to expand the desired Parts Warehouse record. 
in the Locations grid and select Set as Default for Selected Record. The system will alert you to the number of records that will be affected by the action.