To gain the "Good first day." trophy in Firewatch, you must first play through the game's prologue. Just follow all of the on-screen prompts, keep pushing forward and eventually you will reach your firewatch tower. Sit through the conversation on the radio to get to Day 1.
When the day starts, talk on the radio until you spot fireworks going off in the forest. Head downstairs and you'll want to trek straight ahead from the foot of the stairs, west, to the "Cache 306" labelled on your map. Use code 1-2-3-4, copy down the map stuck to the lid, and retrieve the rope.
Keep heading west (when the path forks, the left is fastest). You'll eventually come to a scree slope and be prompted to use your rope. After an incident with the rope, continue west. Push forward past a campsite and through to the lake. Deal with the incident as you see fit.
You can easily grab another trophy here - head north towards "Cache 305". Take what's inside and make a note of the map, then go to the small creek directly north and follow it west towards the lake. At the end of the creek you'll see a turtle on a rock. Press
to pick it up, and hold
to keep it and earn:
The Love Turts trophy in Firewatch worth 25 pointsAdopted a turtle as a pet. The average lifespan of a box turtle is fifty years. It will outlive you. Go back past Cache 305 and take a left (heading east) when you see the creek. You'll want to follow the creek all the way through the canyon while dealing with your radio partner. Eventually you will come across a cave entrance and another Cache, 303. Take the flashlight and note down the map. Go into the cave, head all the way through (you won't be able to open the gate in here) and climb out the other side. Make your way forward and then follow the path that zig zags up the hillside to your right - you'll have to climb some rocks shortly after dealing with another incident. You will resurface behind (to the east of) your tower. Head up for further interesting events, report them in. Eventually Day 1 will be over and you will have earned your trophy.