1. On the stage 'exits' and 'entrances' mean that the actors come on the stage when their role demands and once their role is over they depart to the backstage. In this world, man makes his entrance when he is born and then leads his life. When his life is over he makes his exit from this world when he dies.
2. The poet has compared life to a stage.
3. According to the poet, man goes through life in seven stages. Infancy, childhood, youth, adulthood, middle age, old age and then death