What does Sartre mean when he says that, in our case, “existence precedes essence”, and what do the consequences he draw from this fact (forlornness, anguish, despair) entail for how we should think about our lives?

What does Sartre mean when he says that, in our case, “existence precedes essence”, and what do the consequences he draw from this fact (forlornness, anguish, despair) entail for how we should think about our lives? mean when he says that, in our case, “existence precedes essence”, and what do the consequences he draw from this fact (forlornness, anguish, despair) entail for how we should think about our lives? Explain why you do, or don’t, find his arguments for his position sound.