Minigames such as poker or dominoes do not count toward the achievement.
*Many people are saying this achievement is glitched for them and that their progress tracker isn’t changing so in case this happens to you, make a save at least once in every chapter so you’ll be able to go back to that point if nessecary.*
Just leaving this here so a lot of people don't get screwed over. This achievements description is super misleading, what its asking you to do is to complete a companion mission in chapters 2, 3, and 4.
*Update: It has been confirmed that you must do this in one pl aythrough. Going back to a previous save to do one a mission in a chapter you missed will not work.
*Companion activities will not start showing up until after completing the chapter 2 main quest Blessed are the Meeks?.
It only requires one activity for each of those chapters, hence why it is unlocked during chapter 4. The other camps are not required, just the main.
Below are some of the activities you can do during each chapter, shoutout to PowerPyx for finding these out. If some of the missions aren't available (which sometimes show up on your map as white icons) try progressing the story a little more or by sleeping until the next day. if you're going to progress the story however be careful as to not finish the respective chapter.
Chapter 2:
Any Random Gang Member – Dominoes or Poker: sometimes a random gang member sits at the tables and wants to play (mostly in the evening or at night). *TheOatmeal specifies that you need to completely finish the mini games in order for them to count. *you don’t to win the games, they’ll still count as long as you finish them.
Lenny – Five Finger Fillet: sometimes Lenny sits at a table and wants to play Five Finger Fillet (most in the evening or at night).
Javier – Home Robbery: Talk to Javier at camp, he wants to do a home robbery with you in Valentine. This can still be available in Chapter 3.
Charles – Hunting: Talk to Charles at camp, he wants to hunt a Bison with you.
Chapter 3:
Sean – Coach Robbery: Talk to Sean at camp, he wants to rob a Stagecoach.
Bill – Coach Robbery: Talk to Bill at camp, he wants to rob a Stagecoach.
Tilly – Dominoes Minigame: You can play Dominoes with her at camp when she’s sitting at the tables (usually at night).
Javier – Fishing: Talk to Javier at camp, he wants to go fishing.
Kieran – Fishing: Talk to Kieran at camp and go fishing together.
Micah – Five Finger Fillet: You can play the FFF minigame with Micah in camp when he’s sitting at the tables (usually at night).
Javier – Home Robbery: If you haven’t done his robbery in chapter 2, it may show up again in chapter 3.
Chapter 4:
Charles – Bank Robbery: Only available if you have the Deluxe or Ultimate Edition of the game. This is an exclusive bonus mission, not available with Standard Edition of RDR2.
Micah – Coach Robbery: Talk to Micah at camp, he wants to go rob a stagecoach.
Lenny – Coach Robbery: Talk to Lenny at camp, he wants to go rob a stagecoach.
Pearson – Hunting: Talk to Pearson at camp, he wants to go hunting.
Uncle – Robbery: Talk to Uncle at camp, he wants to go steal some cows with you.