I am not to Fair Isle and new to this type of pattern. The pattern states to knit Yoke first, cast on provisionally and knit from bottom up. And the body of the sweater up down along with the sleeves… OK I get that .
But then the direction go into Raglan Decrease and short row shaping and directions for the collar and then directions for unzipping the provisional cast on and to knit the body and the sleeves down.
Where / When do I knit the Raglan sleeve and the short rows for the back?
I’ve knit the yoke part and I was told buy a knitting shop owner that I need to rip it out and start over and follow the directions step by step but if I do that the Raglan decreases won’t give me enough stitches.
Typically, the short rows are to lift the back of the neck and the raglan line is from collar to the bottom of the armhole.
What is the name of your pattern?
Since the yoke is knit “bottom up” then that provisional cast on determines your stitch count for working the body and sleeves “top down”.
My guess is the raglan Decreases in the yoke are from the armhole up through the yoke to the collar.
So when you finish the yoke that is the neck edge either to cast off or leave on on scrap yarn for later finish.
Unzipping your provisional cast on will leave you with one less stitch for working down the body compared to your yoke cast on count. That is the paradox of knitting both directions from a provisional cast on.
That is my best guess until you can tell us the name of the pattern. (So I can look at the images and instructions.)