[Koha] install koha

[stefan]

Hi,

I'm from Romania, I'm a librarian and I want to install koha on the 
library computer. I tried using the instructions at 
https://wiki.koha-community.org/wiki/Koha_on_ubuntu_-_packages#Install_Ubuntu 
but without success.

  On the computer i have ubuntu 20.04.3.

I want to install koha and then get in the system all the books in the 
library and all the students that come to the library. I want to get 
koha up and running individually on this local computer.

I don't have a system admin at the school.

The computer is connected to the internet.

Can somebody explain to me how i configure /etc/koha/koha-sites.conf? 
Also, what is the difference between web install and IP install. What 
would be best form me? I don't know about domain names and INTRAPORT AND 
OPACPORT...