What are polling agents and special polling agents required to do?

Each validly nominated candidate is permitted under the Election Rules to appoint one polling agent “to attend at each polling station” for such purposes as provided by (the ) Election Rules. Further, the candidate is also permitted to appoint “one special polling agent whose duty it is to be present at the issue of ballot papers at special polling stations and to attend the declaration by the Returning officer, of the result of the poll.”