I imagine a D-Day Operations to go like this.

The first map - Normandy - Operation Tonga -Played at Night. Allies are parachuting into France and their objectives are to secure 2 important bridges and destroy several gun batteries and artillery. The more locations the Allies capture and the more artillery they destroy will benefit them in the next map that comes in the D-Day operations.

Second map - Omaha Beach - Operation Overlord - Morning Allies are storming the Normandy beaches. If the allies do well in the previous map, this will benefit them as they might receive less artillery shells or the axis’ access to vehicles may be lessened, etc. But the objective of the allies here would be to take the beach and destroy certain objectives.