Where the hell do I plug this?

Hi can anyone tell me where I am meant to plug this translucency texture? I’ve never seen this before.

That looks like an opacity/opacity mask. Im not sure what effect your trying to go for though. I would try setting your mat to translucent so u could see what it looks like. Though on a character I couldnt imagine using that unless it was somewhat ghostly.

Looking at your textures I’m guessing it’s for a character, so you set it to subsurface, plug in your subsurface color, and then stick that translucency map into opacity.