The Canadian and British divisions have compiled a standard operating procedure document for North Atlantic control. This document covers procedures for both Gander and Shannon FIRs.
Before attempting to connect to any oceanic position all controllers, regardless of division of origin, must complete oceanic training which is offered by the Shanwick/Gander FIR. Upon completion of this training the controller is rated to work both Gander and Shanwick positions.
It is important to understand that staff of either division have full jurisdiction over both FIRs, and their instructions should be complied with.
Download the sector file for Shanwick and Gander FSS here (Updated 02/03/2019!). Do remember that radar may NOT be used to control.