How to go about a caeser cipher app?

Tried searching but I cant find anything helpful. Essentially I’m wondering how to take a user text input, shifting that input by x characters, and relaying that “encrypted” output to a pre-designated url.
The “encryption” part is what i am stuck on

If you’re trying to create a specific encryption then you would need to start with an algorithm and work step by step to mirror it.

Is the entire algorithm for that encryption method just “shift each character”? If so, that’s not hard to do.

In that case, I would make a list that contains the letter of the alphabet in order from a to z. Loop through the letters of your source text and find the position of each letter in that list (using the “find first occurrence” list block). Use that value to get the list item that is at an index one greater (or seven greater or whatever your choose) than that value. You would need wraparound value support so that if the source letter in your text is z, it knows to mathematically choose an index near the start of the alphabet.

For example, if your target letter is e, then the find value is 5 (e is the fifth letter in the alphabet) and your new letter is f (the sixth letter in thr alphabet.