Short Row Shoulder Shaping

Ive just returned to knitting after a very long break and it seems that what I thought I knew is not the best way these days.
I’ve only ever cast off stitches in “steps” when doing shoulder shapings but when I Googled for the best way to sew these stepped seams up all of the answers came up recommending short row shaping.
So I Googled short row shaping and found a good tutorial on Purl Bee.
I pulled back the shoulders of my cardigan and knitted them again using short rows.
Now I am trying to figure out what to do with the back of the cardigan.
Yes, I can do the short row shoulders but what happens about the neck? It says to cast off three stitches and then again on the following alternate row.
Do I cast the neck stitches off or do I somehow do short rows at both ends of the knitting?
I’m totally confused and hope you can understand my question.
Thanks for any help you can offer.

I still cast off in steps and there are many patterns that are written that way. Not all that much has changed, just maybe some variations, some alternative methods. For the neck shaping, I would cast off the 3sts and any others that are called for on the neck edge. The neck shaping will probably be covered by a collar or neckband.

Thank you for your help - much appreciated.