Controlling objects documentation

Unity Engine
1

I’m a beginner and I want to know more, I went to the documentation page and I didn’t find much help there, I have a few questions.
(Java script)

  1. How do I get objects that are in the hierarchy
  2. How do I get the object the script is “Conencted” to or I “created” it in
  3. Where are some places I can get answers fast about these things among others?
2

I have this, and I want to move a ball forward two units
I don’t know how to get the ball to transform it

#pragma strict

function Start () {

}
function Update () {
if (Input.GetKeyDown(KeyCode.Space)) {
jump = true;
}
}
function FixedUpdate () {
if (jump) {

}
}