Stuck on Rowan "Movie Star Dressing Gown"

[Nobones]

Hello, is anyone familar with this pattern from Rowan? It's in their 'Beads, Button and Lace' book.

I'm stuck at the point of splitting my row into 'front', 'back' and 'middle'. I've managed to get the right amount of stitches on the right needles, now it says 'rejoin yarn and work in pattern'. I'm not sure how to rejoin the yarn and the sequence of the pattern stitches has left me a little confused.

Any suggestions would be gratefully received, thanks.