There's a variation between the schedule if the Lightning or Red Wings survive game 7 on Wednesday.
Game 7 of the 2015 Atlantic Division semifinal series between the Tampa Bay Lightning and the Detroit Red Wings is Wednesday night at Amalie Arena. This you already know. There's no certainty who is going to come out of that one the victor (though opinions aren't truthful until events unfold and wishful thinking is biased), but we do know as of this afternoon that the winner will be heading to Montreal to face the Canadiens immediately,
Game 1 of the Atlantic Division Finals (or Eastern Conference semifinals if you're still using that scale) is Friday at Bell Centre in Montreal.