What will happen if Russia declares war on US?

just explain what do you think. as I believe since there are ton of hackers in Russia, they will first invade the cyber realm belong to US like servers, networks in organizations, NASA's computer system and then satellites, pentagon , etc.. then they will begin from Alaska ,Hawaii ,once they invaded these two states. then they will put bombs on most of important areas like Washington DC, New York ,Los Angeles ,etc...