Please give explanations for each lines of coding to understand by a beginner

Hi

This is a ruby programming.

anyone help me with giving proper explanation step by step for this coding. I need explanations for each lines of coding. I am a beginner for programming.

Here is the question
Gosu Major Cycle
Modify a simple Ruby program to move a shape across the screen by modifying the tasks in the Gosu cycle update() and draw() methods.

Enhance the code provided as follows:

    Add a variable in the initialize() method called shape_x with the initial value of zero.
    Add code into the update() method that will add 10 to shape_x.
    Add code into the draw() method that will draw a shape (square or circle of any visible colour) at the y coordinate of 30 and x coordinate of shape_x.

My coding in text format

require 'gosu'
module ZOrder
BACKGROUND, MIDDLE, TOP = *0..2
end
# Instructions:
# Add a shape_x variable in the following (similar to the cycle one)
# that is initialised to zero then incremented by 10 in update.
# Change the draw method to draw a shape (circle or square)
# (50 pixels in width and height) with a y coordinate of 30
# and an x coordinate of shape_x.
class GameWindow < Gosu::Window
# initialize creates a window with a width an a height
# and a caption. It also sets up any variables to be used.
# This is procedure i.e the return value is 'undefined'
def initialize
super 200, 135, false
self.caption = "Gosu Cycle Example"
@shape_x = 0
# Create and load an image to display
@background_image = Gosu::Image.new("media/earth.png")
# Create and load a font for drawing text on the screen
@font = Gosu::Font.new(20)
@cycle = 0
puts "0. In initialize\n"
end
# Put any work you want done in update
# This is a procedure i.e the return value is 'undefined'
def update
puts "1. In update. Sleeping for one second\n"
@cycle += 1 # add one to the current value of cycle
sleep(1)
@shape_x +=10
end
# the following method is called when you press a mouse
# button or key
def button_down(id)
puts "In Button Down " + id.to_s
end
# Draw (or Redraw) the window
# This is procedure i.e the return value is 'undefined'
def draw
# Draws an image with an x, y and z
#(z determines if it sits on or under other things that are drawn)
@background_image.draw(0, 0, z = ZOrder::BACKGROUND)
@font.draw("Cycle count: #{@cycle}", 10, 10, z = ZOrder::TOP, 1.0, 1.0, Gosu::Color::BLACK)
puts "2. In draw\n"
Gosu.draw_rect(@shape_x, 30, 100, 50, Gosu::Color::BLACK, ZOrder::TOP, mode=:default)
end
end

window = GameWindow.new
window.show