Song Rhythm Tracks shines at arranging!
There are three ways.  It’s your choice.  Check out – http://alivedrumming.com/using-ios-mobile-app-songform-rhythm-tracks/

  1. Select   the song form name  for your song from a list and then choose the number of choruses and the length of any intro’ and ending sections.
  2. Enter     the song form’s list of section lengths, such as “8|8/8|8” instead of selecting song form name.
  3. Lookup  an arrangement based on the title you are giving your track.  If a track with the same title has been shared before you’ll get that arrangement and then you can alter it if you wish.