The ranks are the suggested order to run the scenes between the characters in any given round. So if you have 2, 4 and 5 for ranks, then you would run Rank 2 first, rank 4 second and rank 5 last before moving to the next round.
This is just a suggestion, however, and you can run them in any order you like for that round. Just note the ranks change from round to round, and depending on which character types you include, of course.
Let me know if that helps!