do you knit the back cast off then knit the arms and put those on stitches holders until the end and knit the front because none of the pattens i've read tell you that??
Sort of, there's all kinds of ways to knit a sweater and yes, the patterns do tell you how to do it. Some are done where you knit all the pieces separately, bind them off and sew them together. Some are knit in the round from the bottom up, doing the back and front together and the sleeves separately so you have 3 tubes, then you put all the sts on one circular needle and knit the yoke altogether, either as a raglan or just a yoked sweater, doing the decreases up to the neck. Or you can knit in one piece from the neck down, doing increases until you get to the underarms, then divide off the sleeves sts to holders, finish the body and go back to the sleeves to finish them. Others are knit sleeve to sleeve.
The BO a few sts are for the underam shaping at the armhole. You would BO at the beg of the RS row and finish the row, then BO on the WS row. The next RS row generally has a dec at the beg and end of the row and you do a few of them to shape the curve, then you work straight and BO part of the sts at the shoulder at the beg of the RS rows a couple times until all the sts are gone on the shoulder. How to put the pieces together are usually given at the end under Finishing instructions.
Do you have a specific pattern? If you give us a link we can look at it with you and help you out.