Mirl56 is right! When Log "A" is the size required, and with RIGHT SIDE facing: bind off across the row. However, the last stitch on your needle stays put. Turn your blanket (like you were making a left turn on a street) and start picking up stitches with the new color for Log B.
For my Moderne, I picked up that 'first stitch' of Log B almost in the same hole that the last stitch left over from Log A bindoff row.
When I worked back after the pickup row for Log B, I knit the last two stitches together. The last stitch from Log A, and the first stitch from Log B.
Remember: always bind off with the RIGHT SIDE facing you.
I used a crochet hook to pick up stitches. When my crochet hook had about 20 stitches loaded on it, I fed them off the other end of the crochet hook and onto the awaiting needle. I picked up one stitch in each ridge or stitch.
Hope this helps!
