You don't knit the stitches together, together.... Knit the sleeve stitches, then continuing on the same needle knit the front sts, then the other sleeve sts, then the back sts. At this point they'll all be attached by that one row. Maybe the diagram at the bottom of the page in this pattern - http://www.knitty.com/ISSUEfall02/PATTtopsecret.html
will help you visualize it better. The line at the underarm is where you're attaching the sleeves and the body.