1. From the Welcome page click on the My Tasks.

2. Double-click the backup task or Sync Task you want to modify from the tasks list or right click and choose edit or click Edit Task button.

3. Go to Source/First location tab.

• to Add Files: Click the Files/Folder icon, select the files/folders you want to add and press OK button. 
• to Remove Files: Select the files/folders you want to remove and click the remove button in the upper right corner. To select more files/folders at once, hold shift key down and click the files/folders you want to select.

or

click the Files/Folder icon and uncheck the files and folders you don't want to include anymore in the task.