You are correct to ignore that no stitch box. That is not where you are going wrong. Think of that box as just being there to keep the chart square, even when the stitch count changes back and forth between rows, or to make the stitches line up properly with other rows.
I see that you are worried that you are doing it wrong, because there are 8 no stitch squares and you get 8 extra stitches, so you assume you are doing something wrong there. That’s not it: when you see that nostitch box, don’t slip a stitch or drop it, pretend you haven’t even seen it and look at the next box. This sounds exactly like what you have been doing!
Now I wonder whether the chart includes a stitch repeat which is done 8 times across that row? Like this for example: “(k4, k2tog, no stitch, ssk, k4) 8 times” where you do that bracketed instruction eight times. If that is the case, then perhaps you are confused about a stitch and doing it wrong the same way every time, so that every time you do a repeat, you go past the no stitch box once, and you also mistakenly create an extra stitch once, for a total of 8 extra stitches across the row.
I say, first, do a Google search for anyone else who has knit it, they may have posted a correction if the pattern is wrong. Or check the publisher’s website for corrections to this issue. Or, make sure you are doing the stitches correctly. If you were doing k2tog as just a knit 2 once per repeat, you would get an extra stitch every time. Check out the videos and also written descriptions of all the stitches, to make sure you are doing them right, and maybe use markers between repeats and count stitches until you get this sorted out? You might also like to practise the pattern on bigger needles and wool, perhaps with only 1 repeat instead of 8?