Single player version:
Copy scg01ea.ini and mission.ini files to \RedAlert folder.
Start allied campaign and it will be the first map.

CnCNet multiplayer coop version:
copy TotalWar.mpr to \RedAlert\Missions\
Start CnCNet for Red Alert, create a new game and find the map under missions.


Briefing:

To Field Commander:

The soviets have a secret weapons research facility in a northern archipelago that doubles as an interrogation center.
Use a spy to free our imprisoned commando and get her to conduct sabotage operations to aid you in your attack. 
Destroy the defenses around the prison to receive extra reinforcements.

Good luck.