Once you have the mod installed (I'll skip the install steps because I'm assuming you've already done that if you're reading this guide.)

Open your Black Mesa Folder


Hold down shift and right click the file titled 'bshift'

Select Copy as Path

Now, go to your library, and select Add a non-steam game from the 'Add a Game' menu.

Select ANY .exe file. Add it to your library.

Now, right click the newly added file in your library, select properties.

Paste the the path into both the Target and Start in sections

Then, rename and customize as you please! The mod should launch when you click play, and now you can play BM and BMBS as two seperate games!



That's all! Hope this was helpful.