u/Character_Cow4834

I am starting a new campaign and I don't know how I'm supposed to prepare. I just finished my firat campaign and I am playing with two players from that campaign and one new player. I'm not completely sure what a session zero is or if I make a lore handout? I assumed I should just prepare session 1 but the internet had other ideas. So of course, I came to reddit. What are your thoughts? Thanks!