Hi there, Cindy!
Thanks so much for your great question! This pattern is done completely on double pointed needles, and the instructions are written step-by-step for double pointed needles.
We do have a separate pattern called, "Two Socks at Once" that uses sock yarn (fingering weight) and two circular needles. That pattern also walks you through the process step by step and includes pictures to help you through. :)
Please don't hesitate to ask if you have any more questions!
Thanks & Happy Knitting!
-Marjan & Jaime Marsman