US size 10 needles (note: don't make my mistake. Don't use purple needles with purple Boa. You'll NEVER find that stitch you dropped. EVER. I had to frog (rip it...rip it...) out the first three rows about eight times)
Cast on 22 stitches
Knit about ten rows, then create the keyhole.
Keyhole: knit 11 stitches, turn the scarf then knit them again. Do this for about ten or fifteen rows, then do the same for the 11 stitches on the other side. Knit that side until you have the same amount of stitches, then knit across both sections.
Knit until you run out of boa.
Final dimensions: varies. It's a really stretchy sideways and lengthways.