When you launch the game and go through all the tutorial stuff you will eventually get back to the main screen.
From here you will see a part near the bottom that says
Global | Squad
Click on Squad, then Squad again. (Note: You can also get here from the main screen and clicking the golden Eagle)
From here click Create, give your squad a name and description (optional), set a Type (Invite or Open) and an optional rating requirement and badge. Once you click Save you should get the achievement.