Animating simple motion of line with clean fade not overwriting with background(0)

Thank you @jb4x, the example you posted is a version on steroids of what I am trying to do. I look forward to learning the meaning/purpose of things from Draw lines that go from bottom to top? like:
final int
void createLines
class
private

And I look forward to that.
But do I need to understand those things to achieve my goal?

As you say, start be clearing at the beginning of draw with:

background(color);

And I get what you mean by update position and draw new, but there are two steps I am doing that are nested (is that the proper use of “nested”?)

  1. Draw white lines every (10?) pixels to fill screen equidistant from eachother
    (that’s a for loop right? I also tried while loop)

  2. clear

  3. move location down one pixel and then redraw all the lines

clear and loop so lines all appear to move smoothly down the screen.