What did the allies do prior to the d day invasion

In order to be prepared for D-Day, Allies trained and prepared everything to be sure the invasion was successful.

Firstly, they prepared firing ranges and a vast training regarding landings and amphibious operations. Also, Allies had prepared dummies to throw Germans off because they were going to be deployed on parachutes.

Because of bad weather, Germans were not expecting the invasion, at least not on the date it happened - and this baffled the Germans. - Allies also run phony operations in order to make Germans believe that a convoy was already on the move, and in this way make Germans scatter their defenses and be vulnerable.

Finally, there were approximately 3000 Allied ships and almost 1000 British bombers on D-Day.