I attended a workshop to learn navaho plying. I used pre-dyed alpaca fleece. I found that if I plying left handed was much more manageable and turned out far better result.
The scarf was knitted commencing with three stitches - increase one stitch at start of every second row until desired width - then increase one stitch as before BUT decrease one stitch at the end of each row that you started with increasing one stitch. Continue until desired length then decrease cast off across the row. I then attached a tassel on each end.