I'm kind of picturing that you have 13 stitches on each side? I think you work them by themselves until each side matches up at the center of the back. If that's the case, the directions should tell you how to join them end to end and then how to join them to the body of the sweater.
If that's not the case, can you tell me what you have on your needles now, more specifically?
And don't ever feel bad about asking a question. That's what this place is all about!