I took major inspiration from this when making mine. Instead, I tripled up tin foil and smashed it to to face to get the shape. Went through and accentuated the features, then used modge podge and paper towels to make a plastic like layer.
From what I can tell, he is using a cardboard, not those brown ones. With glue, news papers , masking tape and napkin. And I think he is using either water to help mold the paper, or a paint.