[quote=@Yatagarasu]
<Snipped quote by Nimda>

Alright, so an overview. Natural energy, this kind of energy by that name at least, is a form of energy that exists in the atmosphere and the earth of some universes, usually those with chakra. By gathering the natural energy in their surroundings and combining it with their own chakra, sages are able to enter Sage Mode and use senjutsu. Natural energy circulates all throughout the world, but it is usually imperceptible. In order to use senjutsu, one must first learn to sense the natural energy in their surroundings and draw it into their body, which requires becoming "one with nature" by remaining perfectly still.

To control the natural energy they absorb, the user must balance it with their own physical and spiritual energies, which together make up chakra, in order to create senjutsu chakra. If this balance contains too little natural energy, senjutsu cannot be used, but too much makes the user turn to stone; in the case of humans, they first turn into animals before petrifying. [i]This[/i] is where the danger of sage chakra lies. 

You really only need perfunctory training with sage chakra, since you'll be eating chakra fruit.
[/quote]

What do I have to do to learn it?