Confusion has ensued.

I have just spam read all of berserk up to what is currently released and I just realised there’s like 16 chapters that come before where I started. I don’t know what all the arcs are called so can someone explain where I have started? I started at chapter one and read all the way through then found out there’s like an 0A-16 I think it’s called the Black Swordsman arc? I started it last night and I’m confused about the timeline now because he meets Puck in this timeline so is it set somewhere between the main story arcs or something? I’m literally going to re read the entire manga now but starting from 0A. Did I read the manga wrong by starting at chapter one instead of 0A??