What is the goal of a user story?
A user story is an informal, general explanation of a software feature written from the perspective of the end user or customer. The purpose of a user story is to articulate how a piece of work will deliver a particular value back to the customer.
How are the user role and goal related in a user story?
The user role in the user story is the role that actually is getting the value described in the user story. The role matches the goal! The role is not simply the user. There are different types of users so the role needs to be more specific.