Okay, I think I know how this is put together. The purl stitches on this side will form 2 columns of knit stitches on the other side. These will be the sides of the slipper when you fold it closed, the 14 sts in the middle are the sole. The 'turning ridge' is just for information to let you know where they are later in the pattern when it refers to them. You don't have to do anything different, just follow the pattern as written.
sue- knitting heretic