Which part? Consider reading and understanding https://docs.mojolicious.org//https://learn.perl.org/.

Thanks. This is new to me. All perl for apache or nginx. I was used to use on administration, small tasks. I want to use Mojolicious to websites. This was copied to try to have an email sender on the company. I need to improve more.

I want to use Mojolicious to websites

There are other options which avoid CGI.pm. I have recently changed from hard coding HTML into Perl scripts to using Template. It took a little time to get started with it but it is so much faster and simpler to develop. Pick a framework or templating system and use that, don't even think about CGI.pm