We are given a chocolate bar with $n$ pieces (squares) and we already know by strong induction that $n-1$ are needed to break it in individual parts. https://web.stanford.edu/class/archive/cs/cs103/cs103.1134/lectures/04/Small04.pdf (p. 22)
But now I need to prove this with well-founded induction. My problem is I do not really understand what I should do differently compared to strong induction. I know that we have to do induction over $\mathbb{N}$ and that $\mathbb{N}$ has a well-founded order with $ <$, but how do I proceed from there? and what the is main difference to the usual induction?