This is story related....the only reason I wrote a solution was because I don't want you freaking out like I did when it didn't pop when I thought it would......I had to restart the first mission several times because both boxes weren't checked off........
When you first meet Samuel, he will take you by boat to the Hound Pit......the cheevo pops a few seconds after the boat stops, and you get the objective to meet the Loyalists......
Update: TheAaronLad posted in the comments that his cheevo popped a lot later for him......
So just a warning: This MAY be a "delayed" achievement for some people while it may pop where I posted in the solution.........
Thank you TheAaronLad for the feedback with useful information!!