Once the activities are created in the sheet, you can assign a WBS Code (Select WBS Code window) to a selected activity by using the WBS picker. By default, all of the activities created in the manual activity sheet will show the project-level WBS row as assigned WBS. You can select a single WBS Code from the hierarchy. You can bulk assign the same WBS Code to multiple activities, through drag-and-drop at the cell level within the activity sheet.