Email Policies

I have two questions;

First question; when creating a policy, under internal it has "users", "groups" an "domains". I'm curious as to whether this is an "and" or an "or" statement?

For example, if I add user "matt", "john" and "andrew" under users, and then add group "Admin Staff" and then the customers domain under "domains" does that only apply to matt john and andrew if they are also a member of the "Admin Staff" group, or does it apply to matt, john, andrew AND the "Admin Staff" group.

I've checked the documentation and it doesn't really explain this.

Second question; if I create a policy and don't apply it to any users or groups, but apply it to ALL domains, does that mean that the policy will apply to every mailbox being processed by Sophos? I assumed so, but it looks like this isn't happening

Thanks in advance for your help