Need help creating a macOS sierra USB boot drive to use for a dual-boot partition on my PC

As the title says, I'm having trouble creating a macOS Sierra boot drive that can be used to install a Sierra partition on my custom-built PC.

I've looked around and can't seem to find a way to obtain a copy of Sierra that I can create a boot drive from. I checked the guides on the sidebar but wasn't able to figure it out as it looks like they're mostly updated for Success' href='/2020/12/install-macos-mojave-on-supported-pc.html'>Mojave installs instead. Creating the actual boot drive isn't the problem, I just can't find a way to obtain a copy of the actual Sierra software in order to make the image file. I thought maybe I could make a copy using my own macbook (since its running Sierra) but cloning seems to be for a full backup and not just the OS?

I'm sure I'm just being stupid and not looking around enough, but any help would be appreciated!

Author: @lazytortle