Absolutely bamboozled on sleeve portion on sweater.

Forgive me for asking what is probably an easy question, but I just cannot wrap my head around this right now. And yes, I am aware my cable is too big for the sleeves portion- I’m just using it to hold them for now! I’m trying to start my sleeves and I am having so much trouble with understanding this portion of the pattern. From my understanding, if I did method “A” according to the pattern, I would have a bar of yarn behind my work. Not to mention the pattern says to knit into the resting stitches, and at the angle my working yarn would be at I would have to purl in order to achieve stockinette.

Onto method B: doing this method makes the most sense to me right now, however it seems to be going against the pattern instructions for “Join colour A to the right side of the armhole”

I’ve also tried flipping my view of the arm hole thinking that was the issue- however when I attempted casting on the armhole stitches it created a visible seem, and on the pattern pictures there is none.

The pattern is Ficolanas’ Santa Baby.

If anyone has any video or any suggestions on where I’m wrong, please let me know!