Use this dialog to assign or unassign one or more resources to one or more tasks. The dialog opens when you click the Resources button in the Gantt Chart Toolbar in Schedules.
This is a special version of the Select Resources Dialog. The title bar shows the number of currently selected schedule tasks. When the dialog opens all of the resources that are currently assigned to any of the selected tasks automatically display in the Resources table on the right. After each resource, in parentheses, is the number of the currently selected tasks the resource is assigned to. To assign a resource to all of the selected tasks, drag them from the tree on the left and drop them on the table on the right and then click the Save or Save & Exit button. Notice that when you add them to the table, their "(Assigned to ___)" is 0 and will stay that way until you click the Save or Save & Exit button. To unassign a resource from all of the selected tasks, select them in the Resources table, click the Delete button, and then click the Save or Save & Exit button.
To summarize: All of the resources that are showing in the Resources table at the moment you click the Save or Save & Exit button will be assigned to all of the selected tasks. If there are no resources in the table at that moment, all assignments will be cleared from all of the selected tasks.