Thanks Andre.
I followed the way you suggested.
1.created previledge,duties,roles.
2.created query & security policy & assign the rolename to test rolename.
I am getting below error while opening my custom form.
"Bad container."
"Failed to generate query from database blob"
I want that form should get open but the button control on that form should get hide for specific users.
What value of operation property on policy I should set?
What value of access property on privilege I should set?