This is THE place to start.  It's a quick 4 minute introduction that shows you all the parts of a PySimpleGUI program.

You'll learn the basics of creating a layout, making a window, running an event loop and updating elements in your window to reflect changes.

Important links:

http://www.PySimpleGUI.org - Documentation
http://Cookbook.PySimpleGUI.org - Cookbook 
http://Calls.PySimpleGUI.org - detailed call reference
http://www.PySimpleGUI.com - GitHub
http://Demos.PySimpleGUI.org - Demo Programs
http://Trinket.PySimpleGUI.org - Run a bunch of demos online
http://YouTube.PySimpleGUI.org - Playlist of the current instructional videos
http://Issues.PySimpleGUI.org - File an issue, ask a question, report a bug

Source code for the program presented:

import PySimpleGUI as sg

layout = [[sg.Text('Enter something:'), sg.Input(k='-IN-')],
          [sg.Text('Our output will go here', size=(30,1), k='-OUT-')],
          [sg.Button('OK'), sg.Button('Exit')]]

window = sg.Window('Title', layout)

while True:
    event, values = window.read()

    if event == 'Exit' or event == sg.WIN_CLOSED:
        break

    window['-OUT-'].update(values['-IN-'])

window.close()