There are many resources to assist you here, but the best single source of information I know of is from CPAN itself:
How to Mirror CPAN
That link lists the common options for mirroring CPAN. from there, you will need to set up a web server, which has nothing to do with Perl. Apache is usually the go-to, but it's sort of large and there are smaller servers like mongoose as well. That being said, most operating systems make Apache installation and setup rather easy nowadays, so I would suggest Googling basic Apache configuration for whatever your operating system / distribution is.
You shouldn't need any fancy web server configuration, modules, server-side code, etc., to host a CPAN mirror. A basic static setup will do.