I repeat my analogy of the seeing process
Think of the seeing process. It occurs almost an infinite number of times just in one day. Yet every brief moment of seeing an object arises because of very complex conditions - no one can make it arise, but if the conditions are there it must arise.
We take it for granted but it is at least as amazing that seeing should arise as that satipatthana should arise. From this perspective, then, can you really tell someone how to have satipatthana; it is like trying to explain to someone how to see. If they good eyes (conditioned by kamma and other conditions) then they must see; but if they are without eyes.....
So we don't send children to a special school to train them how to see or hear or taste or smell. If they have eyes and ears, tongue and nose they will experience color, sound etc. al they have to do to see is open their eyes.
But if they don't have eyes or if their eyes are damaged no amount of training , determination, effort and willpower will make seeing occur.
Likewise there are objects such as feeling, hardness, desire, aversion and all the other objects listed in the satipathhana sutta arising all the time . Whether one focuses or doesn't focus. Whether one sits under a tree, urinates, defecates, walks up and down, looks behind, looks in front the objects are appearing. But just as color is beyond the ken of a blind man , so the real nature of each object is hidden to the one without right view.
On the other hand if right view is firm then those same objects start to show their absolute nature, not because one wants them to. Not because wisdom wants to know but simply because the eye of wisdom is open and not impaired.
Then one won't be thinking about some special practice that must be performed anymore than children train to see objects.