In your more descripting comment you write the following:
“1 Lang said: “vedanā-samosaraṇā sabbe dhammā”, translated as “Everything that arises in the mind starts flowing with a sensation on the body.”
2 – Vedana is not just “body sensations” involving just kaya or the body.; see, “Vedana (Feelings)“.
3 – Each and every thought is initiated by a sensation received by any of the six indriya (or ayatana): cakkhu (seeing), sota (hearing), ghana (a smell), jivha (a taste) ,kaya (body sensation), and mano (dhamma coming to the mind).”
The sensations that we are told to observ do not come purely from the mind, are not created only by it. Vedana, as you correctly indicate, come from all the six-senses, plus the atmosphere, the food and the old heavy patterns (sankharas).
So, what we are told to be aware of is the result (effect) of all conctact (factor of pariccasamuppada).
It turn out to be very clear when you are by day 7 to 10… personally I once experienced a vibration from my right ear to the rest of the body when the gong was hitted. There was like dense particles moving like a flow. It was very insightful and at the same time not so much, my equanimity got broken ????