What did the pattern directions tell you to do? Or did it just say to knit a crew neck? It does involve ribbing and circulars, but the pattern should give you a bit more info as to how you should do it for your sweater.
If you are wanting to adapt a pattern you are better off doing a search on knitting patterns for crew necked items and looking at how they are constructed and then considering what to do. Someone here may have a suitable pattern but try: