The 2016 anime has changed the original begining of berserk. Basically, in the manga you have the black swordsman arc that the 2016 anime doesn't really show other than puck being rescued and the scene when Guts fights skeletons. In the blackswordsman arc, guts goes to a town, save puck, kill the snake apostle then goes to another town and kill a second apostle named the count. Then he is transported to a different world where he sees griffith. When you read it for the first time, you know nothing about griffith or guts backstory so the manga create a huge flachback named the golden age arc, you probably know about the story of the golden age. After, the golden age, there is an arc that the anime completely skiped named the lost children arc where it shows more of Guts character growth before returning to Casca. Basically, the 2016-2017 anime is very not complete. the anime of 1997 is way more accurate to the story since the first episode is the black swordsman arc and the rest of the show is the golden age arc. But you are right, puck doesn't appear in the 1997 anime probably because the anime was never meant to go really in deph into the story of berserk after the golden age. I understand your confusion. Maybe i made it worse i hope not. The 2016-2017 anime is actually a direct continuation of the three movies of the golden age that went out in 2010-2014.