thumb attachment

[yarnology]

I've been breezing through the knucks until I got to the thumb joining part. I've looked for help in KALs, but haven't found any answers. My question is this: When I put the body and the thumb on two needles, the working yarn is in the middle of the needle. I don't understand how to start knitting the thumb if the "round" starts in the middle of the needle. Help?

[ladydemetreis]

What I did was put them on the left hand needle and knit those.