Need more details about how to use in other weapons mod

[HK560]

I can see that this framework is a huge help for weapon mods, but my little brain can't quite figure out how to make other weapons also scope models align in the middle of the screen to use these awesome scopes vmt.
I think I need more detailed documentation or readme.

[HK560]

Btw, my blender version is 2.93, but I can't open the .blend file, it said that the file format is not supported. What version of blender are you using?