To unlock the "You Died" trophy in Friday the 13th: The Game, all you need to do is get killed by Jason. You have to do this online -- the offline play and challenges will cast you in the role of Jason rather than a counsellor.
Assuming you can get yourself in a game and are not randomly chosen as Jason, all you need to do is track Jason down and allow yourself to be murdered by him. Bear in mind that Jason will be another player so will move fairly erratically, especially if they don't know what they are doing. If Jason is loudly attacking another player he will appear as a red blip on the map so you could always wait to see this occur and head straight for the source of the horror.