By default, the system assigns all resources at 100% allocation. In reality, a resource often works on a number of different tasks in an interleaved manner. For example, suppose that, for the coming week, a resource should spend half his time on Task A and half his time on Task B. To model this situation in the software, one sets the resource at 50% allocation for each of the tasks. To do this:
open the schedule editing dialog for Task A
click on the first entry in the Resource column of the resource table in the lower left of the dialog, shown below.
a resource selection dialog opens up. Select the desired resource in this dialog and click OK. The resource name is entered into the table.
double-click the Allocation column entry for the resource in the table, and enter 50. Hit the TAB key to finsh the edit.
click the Save changes button to close the dialog.
repeat the above steps for Task B. Now the resource is allocated at 50% to both Task A and Task B.
the schedule changes, and if the resource is not assigned to other tasks, the Gantt chart will show the resource working simultaneously on Task A and Task B, as shown in the figure below.