Add the requester's manager to a field in a ticket

Add the requester's manager to a field in a ticket

I need to populate a field in the ticket when a requester opens  a ticket that pulls the $reportingto$ for that requester into the ticket. Also I need to have the $reportingto$ manager as the first level approver for the ticket.

I'm not sure how to create the custom field and how to set the approver to the requesters manager.