Not sure if the title makes sense or really how to word the question, but what I am trying to have done is the user inputs a sentence per-say, and then it will grab from the other string according to whatever index that letter is and print it to the new string then print the string.
Probably a simpler way, but if you could explain this way and the easier one that would cool maybe you will understand once you see the code.
abc = "abcdefghijklmnopqrstuvwxyz"
caesar_cipher="bcdefghijklmnopqrstuvwxyza"
user = input("Enter what you want ciphered: ")
new_string = ''
print(new_string)