For instructions on how to install Koha on Ubuntu from packages, please
consult http://wiki.koha-community.org/wiki/Koha_on_ubuntu_-_packages

For instructions on how to install Koha on Debian from packages, please
consult https://wiki.koha-community.org/wiki/Debian

If you are a developer, you should take a look at koha-testing-docker or KohaDevBox:
https://gitlab.com/koha-community/koha-testing-docker
https://gitlab.com/koha-community/kohadevbox