Ubuntu 16.04, enabling proxy websites?

Good day you guys, came here trying to find where I missed a configuration or a module.

I have 2 VPSs, 1 running CentOS 7, the other running Ubuntu 16.04. I've got "Edit Proxy Website" already on my CentOS but I really don't exactly remember when or how I've enabled the feature. And it's working wonderfully. Mind you, I am not able to install Squid proxy on that machine. VirtualMin does offer to have it installed and configured for me but when I proceed it throws error.

But on my Ubuntu machine, I see "Edit Forwarding Frame" but I can't get it to work. I created a snapshot of my server and installed Squid Proxy, but it made no difference. Nothing shows in the wrapper.

Am I missing a configuration somewhere to have "Edit Proxy Website" enabled easily? Thank you guys. I'm just getting started with Docker, and this proxy is a big thing for it to make sense for the end users :)

Thanks guys, AllMins are beautiful!