Learn English – How to represent things from up to down

Crouching is different from "bending down." The picture that you have provided is of someone crouching, with his center of gravity in the same vertical plane as it would be were he standing. A person who is bending down would bend be leaning forward with his center of gravity ahead of where it would be were he standing.

To "duck" might imprecisely mean to crouch very quickly, but it could also mean to bend over very quickly or to fall to the ground quickly.

In your first example, you would just use above, as an adverb is all that is needed. But it really only describes what is directly above.

In your second example, from above is not helpful because it is not specific as to what you are referring to. You should point to the specific location.

When using from above, from is a preposition, so I expect an object in that phrase. For example:

From above the trees, I could see the distant horizon.

The locations are specific. Also motion is often involved:

The birds flew from above the trees to the roof of our house.

There are some idiomatic usages though, for example:

Their new baby was a gift from above. (meaning from heaven)