Adapting flat patterns to knit in the round...How?

When changing a pattern…for a sweater, for instance…from knitting it flat as a pattern directs, to knitting in the round, at least to the armholes, is it just as easy as casting on the number of stitches the pattern gives for both the front and back of the piece onto my needles and joining?

Or is there more to it than that?

Thanks!

It can be, though most knitters advise to CO 4 sts less which would used in the seaming. If your gauge is a little on the small side, you’d leave them in.

. . . and remember that if there is any kind of stitch pattern involved, you’d read the directions for the WS rows in the opposite order than they’re written, reversing knits for purls and vice versa, as well.