Ultimately, having a player be captain is up you. In Chapter 10: Gamemastering, in the core rulebook, there’s advice for groups who have a captain as a player character. Some groups work well with one player taking lead, asking for advice but ultimately making the final decision, while others work best when deciding things as a group or following the direction of a Non-Player Character. Make the sure the whole group is happy, whichever style you choose.