You can use the Edit Placement Group dialog to edit the description of a Placement Group resource for the target AWS platform.
In the Web Interface toolbar, select the Platforms tab.
Select the platform, then click Edit.
Under Associations, select the Placement Groups tab, then click Edit (or double-click the placement group) to open the Edit Placement Group dialog.
Modify the Description for the Placement Group resource.
Click Save to update the Placement Group resource.
Click Close to exit the dialog.