I’m not sure if I should post the link to the GitHub - seems to be grey area because it’s based on leaked code.Do you have a source on that, because I haven't heard anyone talking about that. Not Andrew Tsai, not MrMacRight, not even Tyler McVicker and Tyler is the biggest Valve fanboy of them all reporting on any tiniest bit of Half Life news.
Here’s the Reddit link: https://www.reddit.com/r/macgaming/comments/11qrqil
From there I followed one of the comments to the Mac Source Ports discord and there are full instructions in the devtalk channel there.
Due to having to run lots of terminal commands to build the engine, and a terminal command to even launch it, it’s probably not going to feature easily on one of those YouTube channels.