In order to view a diary held in a remote workgroup, go to Diary mode and select the Users drop down list. Select the remote workgroup which will be shown towards the bottom of the list. This will open the remote workgroup and will select the first user's diary in the remote workgroup to which you have access.
If you do not have at least read access to any users' diaries in the remote workgroup, OfficeTalk will warn you with a message and will return you to viewing the local workgroup.
Once you are viewing data in a remote workgroup, then provided that you have sufficient access, you may add, edit and delete data in just the same way that you add, edit and delete data in your local workgroup.