I'm not quite sure if you mean double knitting. Do you mean double knitting, as in having a reverseable potholder? If that's what you mean, then one side will have a black background with a red design, while the other side will have a red background with a black design. If that's what you're going for then see Amy's tutorial for reverseable knitting on this website (it's great!).
If you want the potholder to have a right side and a wrong side, then you'll be doing either intarsia or stranded color work for the design. There are videos on the website for both techniques.
I hope that helps. Can't wait for the design to be posted