You cast on with one color. When it comes time to use another color, for Fair Isle you carry the two colors all the way around or back and forth; for intarsia, you have a separate strand of yarn for each section of color.
"Trust the pattern!"
Time flies like an arrow, but fruit flies like a banana.
Hop aboard while we follow the cloud-covered van of knitting harmony, man!! Woooo!! --Hedgehog
IngridKH on Ravelry