You have never done ML. A PM asks for "a recommendation feature". Same loop?
Answer it out loud before you open anything. The value of the flags below is in comparing them to what you actually said — including whether you asked who uses it before naming what you would build it with.
The situation behind the question
The online store's PM asks for "recommendations, like Amazon". You have built the store and never trained a model. The interviewer asks what your first hour looks like and whether it is different from the first hour on checkout.
What it is really testing
Whether the candidate sees that the problem-solving loop carries across domains — the questions are the same, the next lessons differ — and can find where the loop enters ML: the decision the prediction feeds, the data that exists, the baseline, the metric, and the question of whether a model is needed at all.