Square Off?
As much as I think I have explained how to cut potatoes into the perfect size for french fries like the ones in the Fish and Chip recipe (https://shopitmiseitmakeit.ca/recipe/fish-chips-with-tartar-sauce/), it may be hard to visualize exactly how to do it. There are plenty of videos that will show you how. Below is a good video that shows exactly what I mean by square a potato. Now it goes further and actually takes all the skin off and then proceeds to dice the potato.
For making great french fries, you just need to cut the 4 sides off, then proceed to make the cuts for the fries. Leaving some peel on the ends of the potatoes still makes a tasty fry. ATK is just one of those resources that I rely on if ever I need to learn tried, tested and true cooking techniques. Below is how they demonstrate the skill. As usual, it’s bang on!