define methods in another file

[snippsat]

or can it just be written and the IDE or Python understand what you want and does it?

Yes if don't need stuff from standard library or 3-party module just write code and Python will understand it.

secret_number = 34
tries, guess = 0, 0
while guess != secret_number:
   guess = int(input("Take a guess: "))
   if guess > secret_number:
       print("Lower...")
   elif guess < secret_number:
       print("Higher...")
   tries += 1
    
print('You guessed it! The number was {} in {} tries'.format(guess, tries))

If file called guess.py run with python guess.py

---

If as a example want use math from standard library,it's kind of similar to C++ example
Python:

from math import sqrt

print(sqrt(4))

C++:

#include<iostream>
#include<cmath>
int main(){
    cout<<sqrt(4);
    return 0;
}

---

The concept of import is kind of simple if look at a module.

# foo.py
def add(a, b):
    """This program adds two numbers and return the result."""
    result = a + b
    return result

So now i want to use add function in an other script(file).

# bar.py
from foo import add

a = 11
b = 3
print(add(a, b)) # Use add from foo.py 

Output:
14

Package more stuff than just a couple of files and sharing stuff with wheel or PyPi,
is a more complex,i have long tutorial about here