Object permissions
Create a new permission
Use Menu->Permissions->Edit object permissions menu to open the object permission dialog.
Type in a name of a new permission and click on add button. The new permission will be listed in the Permissions area of dialog.
Datapoint permission
Open treeview and drag&drop one or more datapoints onto the "Datapoints" field.
Mark those permissions that you want to have access to these datpoints. More than one permision can be marked.
Important: By default each datapoint can be accessed by any user. If you include a datapoint in a permission then it will be reachable only those users that have that permission.