I just started to learn about Newton's 3rd law and I still feel kind of rusty in the topic: I have a question on my mind that I just can't figure out. When we push a wall, according to the 3rd law the wall returns the same amount of force the opposite direction and therefore I start to fall backwards. I have wondered why when I lay something on a floor/rigid surface, if the object applies the force of gravitation on the surface why doesn't the object, goes upwards because of the opposite force the floor exerts on the object upwards. I know it has something to do with the gravitational force always acting on the object, but the mechanism of it seems obscure to me, and I'm struggling to truly understand the reason the object remains still on the floor.
Would someone mind to explain the mechanism behind it, why the object remains still and not bounces of the floor upwards with the force of gravity?