I am knitting a scarf that has a hole in the middle to slip the other end of the scarf through. The pattern is saying...
Next Row (RS): K8, bind off 12 sts, k to end.
Next Row (WS): K3, p5, cast on 12 sts over bound off sts of previous row, p5, k3.
I am not sure how to cast on 12 sts over the bound off sts of previous row.
I think you want to cast on 12 stitches onto your needle OVER the place where you bound off on the previous row. After you k3, p5 then, you will just backward loop your yarn over your needle making a cast on, or better yet do the knitted cast or a cable cast on, on for these 12 stitches. This way you won't have as much sagging in the stitches. Then you will have essentially a "hole" which is connected to the rest of your stitches on each end., which is what you say your pattern wants you to do. Another way to think about it is making a big button hole.
Check out this post for more explanation http://www.knittingddaily.com/blogs/howto/archive/2009/02/16/picking-up-stitches.aspx but this is different from what you want to do. Because if you do this you will NOT have the hole. But it will give you some info maybe for another project.
Hopefully you will find this helpful. Have a great day, Heather.
And all the women who were wise of heart spun with their hands, and they kept bringing as yarn the blue thread and the wool dyed reddish purple, the coccus scarlet material and the fine linen. Ex. 35:25