Porting GoldSrc maps

Is there any way to do this? I tried moving the .bsp into the gmod files but that didn’t do shit. I have two maps, drive_in and private_beach_v2, from Half-Life : Opposing Force. I really want them for posing purposes.

Can someone explain how this works? If you can’t port GoldSrc maps, are there any mappers here that could recreate one, possibly both of them?

Mapping forum is there:

You will most likely need to recreate the map in Source Hammer for scratch ( with exception of brushes maybe, using some trickery ).