Principal Doctrine 2: "Death is nothing to us, for that which is dissolved is without sensation; and that which lacks sensation is nothing to us."
I found these questions which dive deeper into the meaning with in this phrase (presented in an article reviewing "Facing death : Epicurus and his critics", by James Warren.
The Epicurean belief that “death is nothing to us” is meant to correct the mistaken beliefs which people have that generate a fear of death. But as JW acutely notes, precisely what is fearful about death is ambiguous. On his analysis, it could include at least four analytically distinct fears: 1) the fear of being dead (namely, of not existing); 2) the fear that one will die (namely, apprehension about being mortal); 3) the fear of premature death (namely, of dying too young or before one has completed one’s goals in life); and 4) the fear of the process of dying. JW claims that “there is no single Epicurean ‘argument against death’. Rather, they had an armoury of arguments which could be deployed against the various different kinds of fear of death”