How to use backend on my website

How can I make a website with backend, I am only seeing how to make it without it

Hi,

I think you might be confused.

To do back-end coding you will need to learn programming languages such as PHP, Java, Node JS, SQL, Python, GoLang.
Depends on what you want to build honestly speaking.

Bellow are some useful links:
https://www.codecademy.com/resources/blog/what-is-front-end/
https://www.codecademy.com/resources/blog/what-is-back-end/

Full Stack is basically someone that has the ability to do both Front-End and Back-End.

https://www.w3schools.com/whatis/whatis_fullstack.asp