Fair Isle seed stitch?

I am fairly new to knitting but have picked up on the basics and a couple advanced techniques pretty easily. (I'm a quick study ^-^) Being the impulsive young lady that I am, I'm trying to knit a scarf in seed stitch (K1 P1) and do one colour on the knits and one colour on the purls, but I am not sure where to place the yarn that is not in the stitch. Do I bring both colours to the front when I purl, and then both to the back when I knit? And if I do bring both colours to the front, do I need to twist them or anything before I purl?