2 days learning Python 3

[Donny]

Hi all.
My name is Don, I have never written any code but would love to learn Python in my old/late years!
I have just joined this forum, sorry for such a newbie question to start with.

I have now been learning Python from a book and some research on the net for 2 days now.
I have been following a book called "Hunting-python" and have hit a snag.The dea was to place a circle on the screen and by using the keyboard left & right keys, move the circle around the screen.
The task set was to add up and down capability. I have # the parts I have added trying to do this but have no idea.
The book goes step by step while teaching how to write a game, but it gives a task to complete but has no answer in the book!
The code I have is:

import pygame, sys
from pygame.locals import *
pygame.init()
pygame.display.set_caption("first program")
screen = pygame.display.set_mode((640,480))
xpos = 50
#ypos = 50
clock = pygame.time.Clock()
while 1:
	clock.tick(60)
	for event in pygame.event.get():
		if event.type == pygame.QUIT:
			sys.exit()
	pressed_keys = pygame.key.get_pressed()
	if pressed_keys[K_RIGHT]:
		xpos += 1
	if pressed_keys[K_LEFT]:
		xpos -= 1
	#if pressed_keys[K_UP]:
		ypos += 1
	#if pressed_keys[K_DOWN]:
		ypos -= 1

	screen.fill((255,255,255))
	pygame.draw.circle(screen,(0,255,0),(xpos,200),20)
	pygame.draw.rect(screen,(0,255,0),(100,100,40,30))
	pygame.display.update()

Can anyone help me please as I would rather resolve this before moving on.

Thank you