A man of Principle.
You must earn the Captains trust by the end of game. Very easy to do. A few places though can easily be missed including one of the most important.
Throughout Sam’s journey you’ll be accompanied by the Captain who will give you tasks to do. One task is related to an achievement.
The Trapper achievement in Metro Exodus worth 43 pointsSet all 5 traps in the SAM'S STORY chapter as the Captain requests.
When you do something for the Captain, a flash of light will go off on the screen. Similar to the good moral points that you do in the main game.
Also make sure you have Hints turned on in your options menu otherwise you’ll miss some of these. These are the things in order: