I’d like to know the answer to this too.
A good start would be to get hold of the film “The Longest Day”. That should give you an idea.
The total plan was very compartmentalized.
The whole of D-Day is in the books and available to read. Winston & FDR were briefed on the general plans but the details were very close holed and the planning/rehearsals were Ike's combined allied staff and the combined allied troops.