Getting Started with GMS Cloud
Click Add and choose from the list, the GMS Cloud accounts to which you wish to give access (these will be users on your domain). If necessary, choose a different address book. Select each account and click Add. Then click OK.
The level of permission access can be set to one of five pre-defined levels or it can be customised as required.
Click OK to save the settings
Either double click the GMS Message Store or click Settings to launch a new dialog. Now, switch to the Advanced tab