What does it mean when the pattern says knit - 8 turn, knit back 8 turn, knit - 8. How do you knit back into row you just knitted?
This instruction sounds like they want you to build up a section of the fabric that bulges. If your row is longer than 8, but you turn back early and knit those 8 stitches again, and then you turn again and knit, you’ll wind up with a wavy section.
Edited to add:
When they say “turn”, they mean turn your work around as if you are going to knit the next row (except you haven’t finished the current row). Just turn it around and start knitting back the other way, and don’t worry that there are a bunch of stitches still on both needles.
Can you post more of a description of the scarf or the pattern? I (or one of the others) might be able to give a clearer answer.
Anise
When you turn you’ll be knitting back over the sts you did on the previous row. Each turn is a new row, even if you didn’t work all the sts.