Map Job to a Resource Role

Summary: We want to use the job mapping to Resource role. Is there a profile option or a process to auto assign the Resource Role to the users?

Content (required): When defining a Resource Role, there a JoB Mapping section. I have mapped a job to a resource role. How will the user who has been assigned the job that was mapped get the Resource Role?

Version (include the version you are using, if applicable): 23B

Code Snippet (add any code snippets that support your topic, if applicable): NA