This is a story related trophy and will unlock before you finish the first mission. For more information please see below.
There are numerous ways that you can find out about the information you’re looking for here. Below is a list of every way I’ve found, there may be more. Bottom line is once you find out the info, the trophy will unlock, so have no fear of missing this trophy.
Speak to the fisherman in his boat and do what he asks, you’ll find him in the water next to a dead whale carcass to the left of the slaughterhouse
Knock out Bundry Rothwild and do the favor Abigail Ames asks of you
Pick up the interrogation note from Rothwild’s office, and bring an unconscious Rothwild to the interrogation room
Pick up the interrogation note from Rothwild’s office, knock out or kill Rothwild, and bring an unconscious Abigail Ames to the interrogation room