How to create a fork of freebsd

[Mathe Eliel]

Hello to the community.
I saw a operating system called pfSense that is based on FreeBSD. It uses
PF firewall filter, I think.

Now, I would like to create a sample OS based on freeBSD. I have a web
application written in PHP and running on Apache Server in a FreeBSD
computer. How can I make this kind of fork of FreeBSD thus I give a .iso
file to my friends containing the webserver, the php application and other
downloaded ports such as apinger, dhcpd? To allow them use my application
without redownloading all those applications but they can install it in a
computer and it starts working?

Thank you very much.j