As a part of my review of Vallejo Metal Color, I’m including a link to my video on how to apply it:
…and some photos of the finished products.
It’s very, very difficult to review this product. It does so many things well that I tend to want to ignore the frustrating stuff. That’s not really good. Here’s the most important thing: you must have at least a tiny bit of patience. Don’t rush it. Let it dry for a few days before you try any weathering or panel darkening or anything else. It has to lose all tackiness before you can apply any kind of powdered pastel or charcoal or graphite.