how to learn flask code example

Example 1: flask tutorials

from flask import Flask
app = Flask(__name__)

@app.route('/')
def hello_world():
   return 'Hello World’

if __name__ == '__main__':
   app.run()

Example 2: flask tutorial

'''
use python and flask(one of the best web frameworks in python) 
as the server-side language and control the look of your web app 
using the front-end languages - html,css, and js...[TRY THE "MVC(model-visual-controlling)" METHOD]
'''
from flask import Flask, render_template #importing the module Flask and its attributes...

app = Flask(__name__)
@app.route('/')

def index():
  return render_template('index.html') #using the index.html file for visual controlling...


if __name__=="__main__":
  app.run()
  
'''
TODO:
<exremely important>
make sure that you :
	Create a new folder called "templates" in the same directory where your python file is saved ,and create a new html file called "index.html", and write your html code there...
    Store all assets and other files(including css files,images,videos,js files,and other html files{if any}) in the same "templates" folder...
'''