VERY easy to do, and I am living proof. This scarf was the third object I've knitted, so my experience was very small.
Just follow the instructions, its all knitting and purling. After a couple of rows, you should start to know if you're doing it right. The wrong side of the scarf always shows the skull image clearly, if you want to quickly check your image.
I just had some trouble figuring out how to do the pattern upside down, if thats what you want to do when you reach the middle of the scarf.
Just follow the written instructions exactly, but starting from the last row. Its just a question of knowing where and what row to start backwards, since, if you're like me, I was knitting some empty lines for the neck section.
If you have any difficulty, do not hesitate to ask