With 2 strands of yarn in contrasting colors, held together, cast on 24 stitches. There should be 48 loops on your needle. Make sure to alternate colors. In this case mine is red/white/red/white and so on.
This is a warning to the Mosier Children: You will probably be getting some 'not so pretty' potholders for Christmas.
Knitting Help - Double Knitting by verypinkknits