How to understand a code

Answer 1

It is similar to learn a new language, for example, which is not your native language. Is not?

Answer 2

You have to learn the syntax. Luckily python syntax is very easy compared to other languages.

num = 0
while num < 11:
print(num, end=' ')
num += 1

This reads:

The variable "num" is assigned the value 0.

While "num" is less than 11, print the value of "num" with the ending being a space

Add 1 to "num"

This would print:

0 1 2 3 4 5 6 7 8 9 10