I suggest using a circular needle for this, simply because you start with so many stitches it makes it easier to see what you’re doing!
It’s worth having some stitch markers or contrasting yarn to keep track of where you are as you establish the ruffles, but once you get going it’s a pretty simple pattern to follow.

Three sizes (S/M/L):

• length: 39 (45/51)cm / 15.5 (17.5/20)in
• width around neck: 44 (47/50)cm / 17 (18.5/19.5)in
• width around bottom (above ruffles): 109 (143/178)cm / 43 (56/70)in

Yarn:
- the quantities are an average based on testing the pattern with wool, acrylic and a mix

Materials:

• main colour approx 360 (550/750)m DK yarn
• contrast colour approx 46 (56/68)m DK yarn
• 10 (13/15) buttons
• 4mm circular needle
• 2 (3/4) spare needles or stitch holders
• spare yarn for markers