First do some research to understand pinhole photography, then ask a specific question that points to what you don't understand. I guarantee you'll get a response.
Sorry, I was one of the 31 views, and I do mess about with pinhole photography, but it wasn't clear to me what you were asking about. I would guess the linked picture is a commercially available pinhole plate -- but neither it nor you say ....
Get yourself a light meter that reads out in EV, or use an in camera meter to get f/stop and shutter speed. That will translate into EV on the scale. Then read around until you find the pinhole's f number for the exposure time. It's too easy.