2012 iMac and OCLP

I’m a newbie to OCLP.

I came across this community by accident.

I have a 2011 i5 iMac that I formatted the drive on so I could do a clean install.

The format worked well and I can do a basic boot up into the page where I can do a new install.

It won’t do a clean install via the internet because the machine is no longer recognised by the Apple server, something about being to old …

I was going to throw the machine out.

But the I saw this community :)

Can I use OCLP to install a newer osx operating system via the internet?

If so, how do I learn how to do this?

Sorry for what maybe simple solutions, it’s all new to me at this level.

Thanks in advance.