Roles are assigned to profiles and permission checks are performed against the authenticated profile's roles when they are performing some action. A profile can be assigned more than one role.
Permissions represent an action a user can perform, like posting a comment or deleting a board. Permissions are granted to roles, and in effect a role is a named set of permissions. Once a role is assigned to a profile, that profile has all of that role's permissions.
Scopes control which resources the role assignment is effective in. A role assignment is valid for one or more scopes.
Resources are the entities that profiles act upon. Resources are things like Applications, Programs, Comment Boards, Chat Rooms, Chat Room Messages, and so on.