The way to arrive at a zone I density for your camera, light meter etc. Is to meter the grey card you have in evenly lit conditions. Focus your camera lens at infinity. Leaving the lens focused at infinity, move the camera to where the card fills the viewfinder. Be careful to not shade the card while doing so. If your meter on the camera indicates 1/60 sec at F 11 (for instance), manually set your camera for four stops less exposure. Then make one exposure at F11 and 1/60 second, the second exposure would be F16 at 1/60 second, the third exposure at F16 and 1/125 of a second, the fourth exposure at f22 and 1/125 second. Shoot your fifth through 8th exposure with no exposure by leaving the lens cap the lens. The above exposures are examples only. Use your meter recommendation, and give a total of four stops less exposure (incrementally as in the example above)plus the four exposures with the lens cap on the lens.
Rewind the film and remove from the camera. In the darkroom remove the film cannister, open it. Process the film according to your film and developer combination recommendations. The negatives that are clear are your exposures with the lens cap on. That will be your base plus fog. The first frame that will give you a density greater then your base plus fog with a measurable density of .10 above FB + fog will be your actual film speed. That typically will fall on the third exposure but not always. For instance if you were using a 125 ISO film and using the example above the third exposure showed a density of .10 above fb+fog then your actual film speed would be 64.
Once you have done that test then the next step will be developing for a Zone VIII density. But you need to do the film speed test first. Come back to this forum when you have it finished.
Always remember exposure is for shadows and development is for highlights. Film speed is the place to begin to get your exposure properly placed.