Reading a pattern

I just got the Big-Needle Knit Afghans book for Christmas. I need help understanding a pattern out of it please. For those that own the book I am working on the Dotted Stripes afghan. It says that the afghan is worked with 3 strands of yarn held together throughout, yet the pattern told me to buy to skeins of color A and B. I have enough skiens to work the main color with 3 strands, but what do I do when it comes to A and B. Are they worked with 1 strand or 2?

It does say that you work with three strands throughout, so I imagine that you’d have to divide your colored skeins into separate balls. Maybe knit with both ends of one and one end of another until the first runs out, then roll the rest into separate balls. Or buy another skein of each. Never can have too much yarn! :teehee: